diff --git a/affine.scad b/affine.scad
index f829112..2b319ee 100644
--- a/affine.scad
+++ b/affine.scad
@@ -1,5 +1,5 @@
 //////////////////////////////////////////////////////////////////////
-// LibFile: matrices.scad
+// LibFile: affine.scad
 //   Matrix math and affine transformation matrices.
 //   To use, add the following lines to the beginning of your file:
 //   ```
diff --git a/attachments.scad b/attachments.scad
index 438b899..d7a82eb 100644
--- a/attachments.scad
+++ b/attachments.scad
@@ -155,7 +155,8 @@ function _str_char_split(s,delim,n=0,acc=[],word="") =
 //
 // Example:
 //   #cylinder(d=5, h=10);
-//   orient_and_anchor([5,5,10], orient=ORIENT_Y, anchor=BACK, orig_anchor=UP) cylinder(d=5, h=10);
+//   orient_and_anchor([5,5,10], orient=ORIENT_Y, anchor=BACK, orig_anchor=BOTTOM)
+//       cylinder(d=5, h=10);
 module orient_and_anchor(
 	size=undef, orient=ORIENT_Z, anchor=CENTER,
 	center=undef, noncentered=BOTTOM,
@@ -194,14 +195,21 @@ module orient_and_anchor(
 				]
 			)
 		) : concat(
-			(anchor==CENTER)? [] : [
-				let(anch = find_anchor(anchor, size.z, size, size2=size2, shift=shift, extra_anchors=anchors, geometry=geometry, two_d=two_d))
-				affine3d_translate(-anch[1])
-			],
 			(orient==ORIENT_Z)? [] : [
 				affine3d_xrot(orient.x),
 				affine3d_yrot(orient.y),
 				affine3d_zrot(orient.z)
+			],
+			(anchor==CENTER)? [] : [
+				let(
+					anchr = is_vector(anchor)? rotate_points3d([anchor], orient, reverse=true)[0] : anchor,
+					anch = find_anchor(
+						anchr, size.z, size, size2=size2,
+						shift=shift, extra_anchors=anchors,
+						geometry=geometry, two_d=two_d
+					)
+				)
+				affine3d_translate(rotate_points3d([-anch[1]],orient)[0])
 			]
 		)
 	));
@@ -436,8 +444,8 @@ module intersect(a, b=undef, keep=undef)
 // Example:
 //   hulling("body")
 //   sphere(d=100, $tags="body") {
-//       attach(CENTER) cube([40,100,100], anchor=CENTER, $tags="body");
-//       attach(CENTER) xcyl(d=40, h=100);
+//       attach(CENTER) cube([40,90,90], anchor=CENTER, $tags="body");
+//       attach(CENTER) xcyl(d=40, h=120, $tags="other");
 //   }
 module hulling(a)
 {
diff --git a/debug.scad b/debug.scad
index c3a2567..d0b7341 100644
--- a/debug.scad
+++ b/debug.scad
@@ -66,7 +66,7 @@ module debug_vertices(vertices, size=1, disabled=false) {
 //   faces    = Array of faces by vertex numbers.
 //   size     = The size of the text used to label the faces and vertices.
 //   disabled = If true, don't draw numbers, and draw children without transparency.  Default = false.
-// Example:
+// Example(EdgesMed):
 //   verts = [for (z=[-10,10], y=[-10,10], x=[-10,10]) [x,y,z]];
 //   faces = [[0,1,2], [1,3,2], [0,4,5], [0,5,1], [1,5,7], [1,7,3], [3,7,6], [3,6,2], [2,6,4], [2,4,0], [4,6,7], [4,7,5]];
 //   debug_faces(vertices=verts, faces=faces, size=2) {
@@ -130,7 +130,7 @@ module debug_faces(vertices, faces, size=1, disabled=false) {
 //   faces = Array of faces by vertex numbers.
 //   txtsize = The size of the text used to label the faces and vertices.
 //   disabled = If true, act exactly like `polyhedron()`.  Default = false.
-// Example:
+// Example(EdgesMed):
 //   verts = [for (z=[-10,10], a=[0:120:359.9]) [10*cos(a),10*sin(a),z]];
 //   faces = [[0,1,2], [5,4,3], [0,3,4], [0,4,1], [1,4,5], [1,5,2], [2,5,3], [2,3,0]];
 //   debug_polyhedron(points=verts, faces=faces, txtsize=1);
diff --git a/examples/attachments.scad b/examples/attachments.scad
index f208b20..dce1262 100644
--- a/examples/attachments.scad
+++ b/examples/attachments.scad
@@ -2,7 +2,7 @@ include <BOSL2/std.scad>
 
 $fn=32;
 
-cuboid([60,40,40], rounding=5, edges=EDGES_Z_ALL, anchor=BOTTOM) {
+cuboid([60,40,40], rounding=5, edges=edges("Z"), anchor=BOTTOM) {
 	attach(TOP, BOTTOM) rounded_prismoid([60,40],[20,20], h=50, r1=5, r2=10) {
 		attach(TOP) cylinder(d=20, h=30) {
 			attach(TOP) cylinder(d1=50, d2=30, h=12);
diff --git a/involute_gears.scad b/involute_gears.scad
index 6184a88..28b1040 100644
--- a/involute_gears.scad
+++ b/involute_gears.scad
@@ -144,12 +144,12 @@ function base_radius(mm_per_tooth=5, number_of_teeth=11, pressure_angle=28)
 // Example(2D):
 //   gear_tooth_profile(mm_per_tooth=5, number_of_teeth=20, pressure_angle=20);
 module gear_tooth_profile(
-	mm_per_tooth    = 3,     //this is the "circular pitch", the circumference of the pitch circle divided by the number of teeth
-	number_of_teeth = 11,    //total number of teeth around the entire perimeter
-	pressure_angle  = 28,    //Controls how straight or bulged the tooth sides are. In degrees.
-	backlash        = 0.0,   //gap between two meshing teeth, in the direction along the circumference of the pitch circle
-	bevelang        = 0.0,   //Gear face angle for bevelled gears.
-	clearance       = undef, //gap between top of a tooth on one gear and bottom of valley on a meshing gear (in millimeters)
+	mm_per_tooth    = 3,
+	number_of_teeth = 11,
+	pressure_angle  = 28,
+	backlash        = 0.0,
+	bevelang        = 0.0,
+	clearance       = undef,
 	interior        = false
 ) {
 	function polar(r,theta)   = r*[sin(theta), cos(theta)];                      //convert polar to cartesian coordinates
@@ -202,12 +202,12 @@ module gear_tooth_profile(
 // Example(2D): Partial Gear
 //   gear2d(mm_per_tooth=5, number_of_teeth=20, teeth_to_hide=15, pressure_angle=20);
 module gear2d(
-	mm_per_tooth    = 3,     //this is the "circular pitch", the circumference of the pitch circle divided by the number of teeth
-	number_of_teeth = 11,    //total number of teeth around the entire perimeter
-	teeth_to_hide   = 0,     //number of teeth to delete to make this only a fraction of a circle
-	pressure_angle  = 28,    //Controls how straight or bulged the tooth sides are. In degrees.
-	clearance       = undef, //gap between top of a tooth on one gear and bottom of valley on a meshing gear (in millimeters)
-	backlash        = 0.0,   //gap between two meshing teeth, in the direction along the circumference of the pitch circle
+	mm_per_tooth    = 3,
+	number_of_teeth = 11,
+	teeth_to_hide   = 0,
+	pressure_angle  = 28,
+	clearance       = undef,
+	backlash        = 0.0,
 	bevelang        = 0.0,
 	interior        = false
 ) {
@@ -291,17 +291,17 @@ module gear2d(
 // Example: Beveled Gear
 //   gear(mm_per_tooth=5, number_of_teeth=20, thickness=10*cos(45), hole_diameter=5, twist=-30, bevelang=45, slices=12, $fa=1, $fs=1);
 module gear(
-	mm_per_tooth    = 3,     //this is the "circular pitch", the circumference of the pitch circle divided by the number of teeth
-	number_of_teeth = 11,    //total number of teeth around the entire perimeter
-	thickness       = 6,     //thickness of gear in mm
-	hole_diameter   = 3,     //diameter of the hole in the center, in mm
-	teeth_to_hide   = 0,     //number of teeth to delete to make this only a fraction of a circle
-	pressure_angle  = 28,    //Controls how straight or bulged the tooth sides are. In degrees.
-	clearance       = undef, //gap between top of a tooth on one gear and bottom of valley on a meshing gear (in millimeters)
-	backlash        = 0.0,   //gap between two meshing teeth, in the direction along the circumference of the pitch circle
-	bevelang        = 0.0,   //angle of bevelled gear face.
-	twist           = undef, //teeth rotate this many degrees from bottom of gear to top.  360 makes the gear a screw with each thread going around once
-	slices          = undef, //Number of slices to divide gear into.  Useful for refining gears with `twist`.
+	mm_per_tooth    = 3,
+	number_of_teeth = 11,
+	thickness       = 6,
+	hole_diameter   = 3,
+	teeth_to_hide   = 0,
+	pressure_angle  = 28,
+	clearance       = undef,
+	backlash        = 0.0,
+	bevelang        = 0.0,
+	twist           = undef,
+	slices          = undef,
 	interior        = false,
 	orient          = ORIENT_Z,
 	anchor          = CENTER
@@ -310,7 +310,7 @@ module gear(
 	c = outer_radius(mm_per_tooth, number_of_teeth, clearance, interior);
 	r = root_radius(mm_per_tooth, number_of_teeth, clearance, interior);
 	p2 = p - (thickness*tan(bevelang));
-	orient_and_anchor([p, p, thickness], orient, anchor, chain=true) {
+	orient_and_anchor([p, p, thickness], orient, anchor, geometry="cylinder", chain=true) {
 		difference() {
 			linear_extrude(height=thickness, center=true, convexity=10, twist=twist, scale=p2/p, slices=slices) {
 				gear2d(
@@ -356,24 +356,48 @@ module gear(
 //   backlash = Gap between two meshing teeth, in the direction along the circumference of the pitch circle
 //   orient = Orientation of the rack.  Use the `ORIENT_` constants from `constants.scad`.  Default: `ORIENT_X`.
 //   anchor = Alignment of the rack.  Use the constants from `constants.scad`.  Default: `RIGHT`.
+// Anchors:
+//   "adendum" = At the tips of the teeth, at the center of rack.
+//   "adendum-left" = At the tips of the teeth, at the left end of the rack.
+//   "adendum-right" = At the tips of the teeth, at the right end of the rack.
+//   "adendum-top" = At the tips of the teeth, at the top of the rack.
+//   "adendum-bottom" = At the tips of the teeth, at the bottom of the rack.
+//   "dedendum" = At the base of the teeth, at the center of rack.
+//   "dedendum-left" = At the base of the teeth, at the left end of the rack.
+//   "dedendum-right" = At the base of the teeth, at the right end of the rack.
+//   "dedendum-top" = At the base of the teeth, at the top of the rack.
+//   "dedendum-bottom" = At the base of the teeth, at the bottom of the rack.
 // Example:
 //   rack(mm_per_tooth=5, number_of_teeth=10, thickness=5, height=5, pressure_angle=20);
 module rack(
-	mm_per_tooth    = 5,    //this is the "circular pitch", the circumference of the pitch circle divided by the number of teeth
-	number_of_teeth = 20,   //total number of teeth along the rack
-	thickness       = 5,    //thickness of rack in mm (affects each tooth)
-	height          = 10,   //height of rack in mm, from tooth top to back of rack.
-	pressure_angle  = 28,   //Controls how straight or bulged the tooth sides are. In degrees.
-	backlash        = 0.0,  //gap between two meshing teeth, in the direction along the circumference of the pitch circle
+	mm_per_tooth    = 5,
+	number_of_teeth = 20,
+	thickness       = 5,
+	height          = 10,
+	pressure_angle  = 28,
+	backlash        = 0.0,
 	clearance       = undef,
-	orient          = ORIENT_X,
-	anchor          = RIGHT
+	orient          = ORIENT_Z,
+	anchor          = CENTER
 ) {
 	a = adendum(mm_per_tooth);
 	d = dedendum(mm_per_tooth, clearance);
 	xa = a * sin(pressure_angle);
 	xd = d * sin(pressure_angle);
-	orient_and_anchor([(number_of_teeth-1)*mm_per_tooth, height, thickness], orient, anchor, orig_orient=ORIENT_X, chain=true) {
+	l = number_of_teeth * mm_per_tooth;
+	anchors = [
+		anchorpt("adendum",         [0,a,0],             BACK),
+		anchorpt("adendum-left",    [-l/2,a,0],          LEFT),
+		anchorpt("adendum-right",   [l/2,a,0],           RIGHT),
+		anchorpt("adendum-top",     [0,a,thickness/2],   UP),
+		anchorpt("adendum-bottom",  [0,a,-thickness/2],  DOWN),
+		anchorpt("dedendum",        [0,-d,0],            BACK),
+		anchorpt("dedendum-left",   [-l/2,-d,0],         LEFT),
+		anchorpt("dedendum-right",  [l/2,-d,0],          RIGHT),
+		anchorpt("dedendum-top",    [0,-d,thickness/2],  UP),
+		anchorpt("dedendum-bottom", [0,-d,-thickness/2], DOWN),
+	];
+	orient_and_anchor([l, 2*abs(a-height), thickness], orient, anchor, anchors=anchors, chain=true) {
 		left((number_of_teeth-1)*mm_per_tooth/2) {
 			linear_extrude(height = thickness, center = true, convexity = 10) {
 				for (i = [0:number_of_teeth-1] ) {
diff --git a/joiners.scad b/joiners.scad
index 915d671..98da13b 100644
--- a/joiners.scad
+++ b/joiners.scad
@@ -34,7 +34,7 @@ module half_joiner_clear(h=20, w=10, a=30, clearance=0, overlap=0.01, orient=ORI
 	guide_size = w/3;
 	guide_width = 2*(dmnd_height/2-guide_size)*tan(a);
 
-	orient_and_anchor([w, guide_width, h], orient, anchor, orig_orient=ORIENT_Y, chain=true) {
+	orient_and_anchor([w, guide_width, h], orient, anchor, orig_orient=ORIENT_Y) {
 		union() {
 			yspread(overlap, n=overlap>0? 2 : 1) {
 				difference() {
@@ -50,7 +50,6 @@ module half_joiner_clear(h=20, w=10, a=30, clearance=0, overlap=0.01, orient=ORI
 			}
 			if (overlap>0) cube([w+clearance, overlap+0.001, h], center=true);
 		}
-		children();
 	}
 }
 
@@ -87,7 +86,7 @@ module half_joiner(h=20, w=10, l=10, a=30, screwsize=undef, guides=true, slop=PR
 		}
 	}
 	render(convexity=12)
-	orient_and_anchor([w, 2*l, h], orient, anchor, orig_orient=ORIENT_Y, chain=true) {
+	orient_and_anchor([w, 2*l, h], orient, anchor, orig_orient=ORIENT_Y) {
 		difference() {
 			union() {
 				// Make base.
@@ -133,7 +132,6 @@ module half_joiner(h=20, w=10, l=10, a=30, screwsize=undef, guides=true, slop=PR
 				yrot(90) cylinder(r=screwsize*1.1/2, h=w+1, center=true, $fn=12);
 			}
 		}
-		children();
 	}
 }
 //half_joiner(screwsize=3, orient=ORIENT_Z, anchor=UP);
@@ -171,7 +169,7 @@ module half_joiner2(h=20, w=10, l=10, a=30, screwsize=undef, guides=true, orient
 	}
 
 	render(convexity=12)
-	orient_and_anchor([w, 2*l, h], orient, anchor, orig_orient=ORIENT_Y, chain=true) {
+	orient_and_anchor([w, 2*l, h], orient, anchor, orig_orient=ORIENT_Y) {
 		difference() {
 			union () {
 				fwd(l/2) cube(size=[w, l, h], center=true);
@@ -186,7 +184,6 @@ module half_joiner2(h=20, w=10, l=10, a=30, screwsize=undef, guides=true, orient
 				xcyl(r=screwsize*1.1/2, l=w+1, $fn=12);
 			}
 		}
-		children();
 	}
 }
 
@@ -217,12 +214,11 @@ module joiner_clear(h=40, w=10, a=30, clearance=0, overlap=0.01, orient=ORIENT_Y
 	guide_size = w/3;
 	guide_width = 2*(dmnd_height/2-guide_size)*tan(a);
 
-	orient_and_anchor([w, guide_width, h], orient, anchor, orig_orient=ORIENT_Y, chain=true) {
+	orient_and_anchor([w, guide_width, h], orient, anchor, orig_orient=ORIENT_Y) {
 		union() {
 			up(h/4) half_joiner_clear(h=h/2.0-0.01, w=w, a=a, overlap=overlap, clearance=clearance);
 			down(h/4) half_joiner_clear(h=h/2.0-0.01, w=w, a=a, overlap=overlap, clearance=-0.01);
 		}
-		children();
 	}
 }
 
@@ -245,7 +241,7 @@ module joiner_clear(h=40, w=10, a=30, clearance=0, overlap=0.01, orient=ORIENT_Y
 //   anchor = Alignment of the shape by the axis-negative (size1) end.  Use the constants from `constants.scad`.  Default: `CENTER`.
 // Examples:
 //   joiner(screwsize=3, orient=ORIENT_X);
-//   joiner(w=10, l=10, h=40, orient=ORIENT_X) cuboid([10, 10*2, 40], anchor=LEFT);
+//   joiner(w=10, l=10, h=40, orient=ORIENT_X) cuboid([10, 10*2, 40], anchor=RIGHT);
 module joiner(h=40, w=10, l=10, a=30, screwsize=undef, guides=true, slop=PRINTER_SLOP, orient=ORIENT_Y, anchor=CENTER)
 {
 	if ($children > 0) {
@@ -254,12 +250,11 @@ module joiner(h=40, w=10, l=10, a=30, screwsize=undef, guides=true, slop=PRINTER
 			joiner_clear(h=h, w=w, a=a, clearance=0.1, orient=orient, anchor=anchor);
 		}
 	}
-	orient_and_anchor([w, 2*l, h], orient, anchor, orig_orient=ORIENT_Y, chain=true) {
+	orient_and_anchor([w, 2*l, h], orient, anchor, orig_orient=ORIENT_Y) {
 		union() {
 			up(h/4) half_joiner(h=h/2, w=w, l=l, a=a, screwsize=screwsize, guides=guides, slop=slop);
 			down(h/4) half_joiner2(h=h/2, w=w, l=l, a=a, screwsize=screwsize, guides=guides);
 		}
-		children();
 	}
 }
 
@@ -293,11 +288,10 @@ module joiner_pair_clear(spacing=100, h=40, w=10, a=30, n=2, clearance=0, overla
 	guide_size = w/3;
 	guide_width = 2*(dmnd_height/2-guide_size)*tan(a);
 
-	orient_and_anchor([spacing+w, guide_width, h], orient, anchor, orig_orient=ORIENT_Y, chain=true) {
+	orient_and_anchor([spacing+w, guide_width, h], orient, anchor, orig_orient=ORIENT_Y) {
 		xspread(spacing, n=n) {
 			joiner_clear(h=h, w=w, a=a, clearance=clearance, overlap=overlap);
 		}
-		children();
 	}
 }
 
@@ -322,7 +316,7 @@ module joiner_pair_clear(spacing=100, h=40, w=10, a=30, n=2, clearance=0, overla
 //   orient = Orientation of the shape.  Use the `ORIENT_` constants from `constants.scad`.  Default: `ORIENT_Y`.
 //   anchor = Alignment of the shape by the axis-negative (size1) end.  Use the constants from `constants.scad`.  Default: `CENTER`.
 // Examples:
-//   joiner_pair(spacing=50, l=10, orient=ORIENT_X) cuboid([10, 50+10-0.1, 40], anchor=LEFT);
+//   joiner_pair(spacing=50, l=10, orient=ORIENT_X) cuboid([10, 50+10-0.1, 40], anchor=RIGHT);
 //   joiner_pair(spacing=50, l=10, n=2, orient=ORIENT_X);
 //   joiner_pair(spacing=50, l=10, n=3, alternate=false, orient=ORIENT_X);
 //   joiner_pair(spacing=50, l=10, n=3, alternate=true, orient=ORIENT_X);
@@ -335,7 +329,7 @@ module joiner_pair(spacing=100, h=40, w=10, l=10, a=30, n=2, alternate=true, scr
 			joiner_pair_clear(spacing=spacing, h=h, w=w, a=a, clearance=0.1, orient=orient, anchor=anchor);
 		}
 	}
-	orient_and_anchor([spacing+w, 2*l, h], orient, anchor, orig_orient=ORIENT_Y, chain=true) {
+	orient_and_anchor([spacing+w, 2*l, h], orient, anchor, orig_orient=ORIENT_Y) {
 		left((n-1)*spacing/2) {
 			for (i=[0:n-1]) {
 				right(i*spacing) {
@@ -345,7 +339,6 @@ module joiner_pair(spacing=100, h=40, w=10, l=10, a=30, n=2, alternate=true, scr
 				}
 			}
 		}
-		children();
 	}
 }
 
@@ -377,13 +370,12 @@ module joiner_quad_clear(xspacing=undef, yspacing=undef, spacing1=undef, spacing
 {
 	spacing1 = first_defined([spacing1, xspacing, 100]);
 	spacing2 = first_defined([spacing2, yspacing, 50]);
-	orient_and_anchor([w+spacing1, spacing2, h], orient, anchor, orig_orient=ORIENT_Y, chain=true) {
+	orient_and_anchor([w+spacing1, spacing2, h], orient, anchor, orig_orient=ORIENT_Y) {
 		zrot_copies(n=2) {
 			back(spacing2/2) {
 				joiner_pair_clear(spacing=spacing1, n=n, h=h, w=w, a=a, clearance=clearance, overlap=overlap);
 			}
 		}
-		children();
 	}
 }
 
@@ -423,13 +415,12 @@ module joiner_quad(spacing1=undef, spacing2=undef, xspacing=undef, yspacing=unde
 			joiner_quad_clear(spacing1=spacing1, spacing2=spacing2, h=h, w=w, a=a, clearance=0.1, orient=orient, anchor=anchor);
 		}
 	}
-	orient_and_anchor([w+spacing1, spacing2, h], orient, anchor, orig_orient=ORIENT_Y, chain=true) {
+	orient_and_anchor([w+spacing1, spacing2, h], orient, anchor, orig_orient=ORIENT_Y) {
 		zrot_copies(n=2) {
 			back(spacing2/2) {
 				joiner_pair(spacing=spacing1, n=n, h=h, w=w, l=l, a=a, screwsize=screwsize, guides=guides, slop=slop);
 			}
 		}
-		children();
 	}
 }
 
diff --git a/linear_bearings.scad b/linear_bearings.scad
index 72852ca..e4909b5 100644
--- a/linear_bearings.scad
+++ b/linear_bearings.scad
@@ -80,26 +80,43 @@ function get_lmXuu_bearing_length(size) = lookup(size, [
 //   anchor = Alignment of the housing by the axis-negative (size1) end.  Use the constants from `constants.scad`.  Default: `UP`
 // Example:
 //   linear_bearing_housing(d=19, l=29, wall=2, tab=6, screwsize=2.5);
-module linear_bearing_housing(d=15, l=24, tab=7, gap=5, wall=3, tabwall=5, screwsize=3, orient=ORIENT_X, anchor=UP)
+module linear_bearing_housing(d=15, l=24, tab=7, gap=5, wall=3, tabwall=5, screwsize=3, orient=ORIENT_X, anchor=BOTTOM)
 {
 	od = d+2*wall;
 	ogap = gap+2*tabwall;
 	tabh = tab/2+od/2*sqrt(2)-ogap/2;
-	orient_and_anchor([l, od, od], orient, anchor, orig_orient=ORIENT_X, chain=true) {
+	h = od+tab/2;
+	anchors = [
+		anchorpt("axis", [0,0,-tab/2/2]),
+		anchorpt("screw", [0,2-ogap/2,tabh-tab/2/2],FWD),
+		anchorpt("nut", [0,ogap/2-2,tabh-tab/2/2],FWD)
+	];
+	orient_and_anchor([l, od, h], orient, anchor, anchors=anchors, orig_orient=ORIENT_X, chain=true) {
+		down(tab/2/2)
 		difference() {
 			union() {
+				// Housing
 				zrot(90) teardrop(r=od/2,h=l);
-				up(tabh) cube(size=[l,ogap,tab+0.05], center=true);
-				down(od/4) cube(size=[l,od,od/2], center=true);
+
+				// Base
+				cube([l,od,od/2], anchor=TOP);
+
+				// Tabs
+				cube([l,ogap,od/2+tab/2], anchor=BOTTOM);
 			}
+
+			// Clear bearing space
 			zrot(90) teardrop(r=d/2,h=l+0.05);
-			up((d*sqrt(2)+tab)/2)
-				cube(size=[l+0.05,gap,d+tab], center=true);
+
+			// Clear gap
+			cube([l+0.05,gap,od], anchor=BOTTOM);
+
 			up(tabh) {
-				fwd(ogap/2-2+0.01)
-					xrot(90) screw(screwsize=screwsize*1.06, screwlen=ogap, headsize=screwsize*2, headlen=10);
-				back(ogap/2+0.01)
-					xrot(90) metric_nut(size=screwsize, hole=false);
+				// Screwhole
+				fwd(ogap/2-2+0.01) xrot(90) screw(screwsize=screwsize*1.06, screwlen=ogap, headsize=screwsize*2, headlen=10);
+
+				// Nut holder
+				back(ogap/2-2+0.01) xrot(90) metric_nut(size=screwsize, hole=false);
 			}
 		}
 		children();
@@ -121,7 +138,7 @@ module linear_bearing_housing(d=15, l=24, tab=7, gap=5, wall=3, tabwall=5, screw
 //   anchor = Alignment of the housing by the axis-negative (size1) end.  Use the constants from `constants.scad`.  Default: `UP`
 // Example:
 //   lmXuu_housing(size=10, wall=2, tab=6, screwsize=2.5);
-module lmXuu_housing(size=8, tab=7, gap=5, wall=3, tabwall=5, screwsize=3, orient=ORIENT_X, anchor=UP)
+module lmXuu_housing(size=8, tab=7, gap=5, wall=3, tabwall=5, screwsize=3, orient=ORIENT_X, anchor=BOTTOM)
 {
 	d = get_lmXuu_bearing_diam(size);
 	l = get_lmXuu_bearing_length(size);
diff --git a/masks.scad b/masks.scad
index 76383da..4168eff 100644
--- a/masks.scad
+++ b/masks.scad
@@ -164,8 +164,8 @@ module cylinder_mask(
 //   anchor = Alignment of the mask.  Use the constants from `constants.h`.  Default: centered.
 // Example:
 //   difference() {
-//       cube(50);
-//       #chamfer_mask(l=50, chamfer=10, orient=ORIENT_X, anchor=BOTTOM);
+//       cube(50, anchor=BOTTOM+FRONT);
+//       #chamfer_mask(l=50, chamfer=10, orient=ORIENT_X);
 //   }
 module chamfer_mask(l=1, chamfer=1, orient=ORIENT_Z, anchor=CENTER) {
 	orient_and_anchor([chamfer*2, chamfer*2, l], orient, anchor, chain=true) {
@@ -188,8 +188,8 @@ module chamfer_mask(l=1, chamfer=1, orient=ORIENT_Z, anchor=CENTER) {
 //   anchor = Alignment of the cylinder.  Use the constants from constants.h.  Default: centered.
 // Example:
 //   difference() {
-//       left(40) cube(80);
-//       #chamfer_mask_x(l=80, chamfer=20);
+//       cube(50, anchor=BOTTOM+FRONT);
+//       #chamfer_mask_x(l=50, chamfer=10);
 //   }
 module chamfer_mask_x(l=1.0, chamfer=1.0, anchor=CENTER) {
 	chamfer_mask(l=l, chamfer=chamfer, orient=ORIENT_X, anchor=anchor) children();
@@ -209,8 +209,8 @@ module chamfer_mask_x(l=1.0, chamfer=1.0, anchor=CENTER) {
 //   anchor = Alignment of the cylinder.  Use the constants from constants.h.  Default: centered.
 // Example:
 //   difference() {
-//       fwd(40) cube(80);
-//       right(80) #chamfer_mask_y(l=80, chamfer=20);
+//       cube(50, anchor=BOTTOM+RIGHT);
+//       #chamfer_mask_y(l=50, chamfer=10);
 //   }
 module chamfer_mask_y(l=1.0, chamfer=1.0, anchor=CENTER) {
 	chamfer_mask(l=l, chamfer=chamfer, orient=ORIENT_Y, anchor=anchor) children();
@@ -230,8 +230,8 @@ module chamfer_mask_y(l=1.0, chamfer=1.0, anchor=CENTER) {
 //   anchor = Alignment of the cylinder.  Use the constants from constants.h.  Default: centered.
 // Example:
 //   difference() {
-//       down(40) cube(80);
-//       #chamfer_mask_z(l=80, chamfer=20);
+//       cube(50, anchor=FRONT+RIGHT);
+//       #chamfer_mask_z(l=50, chamfer=10);
 //   }
 module chamfer_mask_z(l=1.0, chamfer=1.0, anchor=CENTER) {
 	chamfer_mask(l=l, chamfer=chamfer, orient=ORIENT_Z, anchor=anchor) children();
@@ -295,6 +295,11 @@ module chamfer(chamfer=1, size=[1,1,1], edges=EDGES_ALL)
 //       cylinder(r=50, h=100, center=true);
 //       up(50) #chamfer_cylinder_mask(r=50, chamfer=10);
 //   }
+// Example:
+//   difference() {
+//       cylinder(r=50, h=100, center=true);
+//       up(50) chamfer_cylinder_mask(r=50, chamfer=10);
+//   }
 module chamfer_cylinder_mask(r=undef, d=undef, chamfer=0.25, ang=45, from_end=false, orient=ORIENT_Z)
 {
 	r = get_radius(r=r, d=d, dflt=1);
@@ -325,6 +330,12 @@ module chamfer_cylinder_mask(r=undef, d=undef, chamfer=0.25, ang=45, from_end=fa
 //       up(50) #chamfer_hole_mask(d=50, chamfer=10);
 //   }
 // Example:
+//   difference() {
+//       cube(100, center=true);
+//       cylinder(d=50, h=100.1, center=true);
+//       up(50) chamfer_hole_mask(d=50, chamfer=10);
+//   }
+// Example:
 //   chamfer_hole_mask(d=100, chamfer=25, ang=30, overage=10);
 module chamfer_hole_mask(r=undef, d=undef, chamfer=0.25, ang=45, from_end=false, overage=0.1, orient=ORIENT_Z, anchor=CENTER)
 {
@@ -659,6 +670,12 @@ module rounding_cylinder_mask(r=1.0, rounding=0.25)
 //     cylinder(r=50, h=100.1, center=true);
 //     up(50) #rounding_hole_mask(r=50, rounding=10);
 //   }
+// Example(Med):
+//   difference() {
+//     cube([150,150,100], center=true);
+//     cylinder(r=50, h=100.1, center=true);
+//     up(50) rounding_hole_mask(r=50, rounding=10);
+//   }
 // Example:
 //   rounding_hole_mask(r=40, rounding=20, $fa=2, $fs=2);
 module rounding_hole_mask(r=undef, d=undef, rounding=0.25, overage=0.1, orient=ORIENT_Z, anchor=CENTER)
diff --git a/metric_screws.scad b/metric_screws.scad
index fe5ba1b..f4d007d 100644
--- a/metric_screws.scad
+++ b/metric_screws.scad
@@ -393,12 +393,12 @@ module screw(
 	anchor="base"
 ) {
 	sides = max(12, segs(screwsize/2));
-	algn = countersunk? DOWN : anchor;
+	algn = countersunk? TOP : anchor;
 	anchors = [
 		anchorpt("base", [0,0,-headlen/2+screwlen/2]),
 		anchorpt("sunken", [0,0,(headlen+screwlen)/2-0.01])
 	];
-	orient_and_anchor([headsize, headsize, headlen+screwlen], orient, algn, anchors=anchors, chain=true) {
+	orient_and_anchor([screwsize, screwsize, headlen+screwlen], orient, algn, anchors=anchors, geometry="cylinder", chain=true) {
 		down(headlen/2-screwlen/2) {
 			down(screwlen/2) {
 				if (pitch == undef) {
diff --git a/nema_steppers.scad b/nema_steppers.scad
index afdc0a5..4273d5b 100644
--- a/nema_steppers.scad
+++ b/nema_steppers.scad
@@ -100,7 +100,7 @@ function nema_motor_screw_depth(size) = lookup(size, [
 //   shaft = Shaft diameter. Default: 5mm
 //   shaft_len = Length of shaft protruding out the top of the stepper motor.  Default: 20mm
 //   orient = Orientation of the stepper.  Use the `ORIENT_` constants from `constants.scad`.  Default: `ORIENT_Z`.
-//   anchor = Alignment of the stepper.  Use the constants from `constants.scad`.  Default: `DOWN`.
+//   anchor = Alignment of the stepper.  Use the constants from `constants.scad`.  Default: `TOP`.
 // Extra Anchors:
 //   "shaft-top" = The top of the shaft.
 //   "shaft-middle" = The middle of the shaft.
@@ -112,7 +112,7 @@ function nema_motor_screw_depth(size) = lookup(size, [
 //   "screw4" = The screw-hole in the X+Y- quadrant.
 // Example:
 //   nema11_stepper();
-module nema11_stepper(h=24, shaft=5, shaft_len=20, orient=ORIENT_Z, anchor=DOWN)
+module nema11_stepper(h=24, shaft=5, shaft_len=20, orient=ORIENT_Z, anchor=TOP)
 {
 	size = 11;
 	motor_width = nema_motor_width(size);
@@ -163,7 +163,7 @@ module nema11_stepper(h=24, shaft=5, shaft_len=20, orient=ORIENT_Z, anchor=DOWN)
 //   shaft = Shaft diameter. Default: 5mm
 //   shaft_len = Length of shaft protruding out the top of the stepper motor.  Default: 24mm
 //   orient = Orientation of the stepper.  Use the `ORIENT_` constants from `constants.scad`.  Default: `ORIENT_Z`.
-//   anchor = Alignment of the stepper.  Use the constants from `constants.scad`.  Default: `DOWN`.
+//   anchor = Alignment of the stepper.  Use the constants from `constants.scad`.  Default: `TOP`.
 // Extra Anchors:
 //   "shaft-top" = The top of the shaft.
 //   "shaft-middle" = The middle of the shaft.
@@ -175,7 +175,7 @@ module nema11_stepper(h=24, shaft=5, shaft_len=20, orient=ORIENT_Z, anchor=DOWN)
 //   "screw4" = The screw-hole in the X+Y- quadrant.
 // Example:
 //   nema14_stepper();
-module nema14_stepper(h=24, shaft=5, shaft_len=24, orient=ORIENT_Z, anchor=DOWN)
+module nema14_stepper(h=24, shaft=5, shaft_len=24, orient=ORIENT_Z, anchor=TOP)
 {
 	size = 14;
 	motor_width = nema_motor_width(size);
@@ -226,7 +226,7 @@ module nema14_stepper(h=24, shaft=5, shaft_len=24, orient=ORIENT_Z, anchor=DOWN)
 //   shaft = Shaft diameter. Default: 5mm
 //   shaft_len = Length of shaft protruding out the top of the stepper motor.  Default: 20mm
 //   orient = Orientation of the stepper.  Use the `ORIENT_` constants from `constants.scad`.  Default: `ORIENT_Z`.
-//   anchor = Alignment of the stepper.  Use the constants from `constants.scad`.  Default: `DOWN`.
+//   anchor = Alignment of the stepper.  Use the constants from `constants.scad`.  Default: `TOP`.
 // Extra Anchors:
 //   "shaft-top" = The top of the shaft.
 //   "shaft-middle" = The middle of the shaft.
@@ -308,7 +308,7 @@ module nema17_stepper(h=34, shaft=5, shaft_len=20, orient=ORIENT_Z, anchor=TOP)
 //   shaft = Shaft diameter. Default: 6.35mm
 //   shaft_len = Length of shaft protruding out the top of the stepper motor.  Default: 25mm
 //   orient = Orientation of the stepper.  Use the `ORIENT_` constants from `constants.scad`.  Default: `ORIENT_Z`.
-//   anchor = Alignment of the stepper.  Use the constants from `constants.scad`.  Default: `DOWN`.
+//   anchor = Alignment of the stepper.  Use the constants from `constants.scad`.  Default: `TOP`.
 // Extra Anchors:
 //   "shaft-top" = The top of the shaft.
 //   "shaft-middle" = The middle of the shaft.
@@ -373,7 +373,7 @@ module nema23_stepper(h=50, shaft=6.35, shaft_len=25, orient=ORIENT_Z, anchor=TO
 //   shaft = Shaft diameter. Default: 12.7mm
 //   shaft_len = Length of shaft protruding out the top of the stepper motor.  Default: 32mm
 //   orient = Orientation of the stepper.  Use the `ORIENT_` constants from `constants.scad`.  Default: `ORIENT_Z`.
-//   anchor = Alignment of the stepper.  Use the constants from `constants.scad`.  Default: `DOWN`.
+//   anchor = Alignment of the stepper.  Use the constants from `constants.scad`.  Default: `TOP`.
 // Extra Anchors:
 //   "shaft-top" = The top of the shaft.
 //   "shaft-middle" = The middle of the shaft.
diff --git a/paths.scad b/paths.scad
index e103407..189531f 100644
--- a/paths.scad
+++ b/paths.scad
@@ -207,16 +207,13 @@ module extrude_from_to(pt1, pt2, convexity=undef, twist=undef, scale=undef, slic
 //       circle(r=40, $fn=6);
 module extrude_2d_hollow(wall=2, height=50, twist=90, slices=60, center=undef, orient=ORIENT_Z, anchor=BOTTOM)
 {
-	orient_and_anchor([0,0,height], orient, anchor, center, chain=true) {
-		linear_extrude(height=height, twist=twist, slices=slices, center=true) {
-			difference() {
+	linear_extrude(height=height, twist=twist, slices=slices, center=true) {
+		difference() {
+			children();
+			offset(r=-wall) {
 				children();
-				offset(r=-wall) {
-					children();
-				}
 			}
 		}
-		children();
 	}
 }
 
@@ -427,7 +424,7 @@ module trace_polyline(pline, N=1, showpts=false, size=1, color="yellow") {
 //   points = The array of 2D polygon vertices.
 //   paths = The path connections between the vertices.
 //   convexity = The max number of walls a ray can pass through the given polygon paths.
-// Example(2D):
+// Example(Big2D):
 //   debug_polygon(
 //       points=concat(
 //           path2d_regular_ngon(r=10, n=8),
diff --git a/scripts/docs_gen.py b/scripts/docs_gen.py
index c534789..758399a 100755
--- a/scripts/docs_gen.py
+++ b/scripts/docs_gen.py
@@ -145,11 +145,14 @@ class ImageProcessing(object):
                     "--imgsize={}".format(imgsizes[0]),
                     "--hardwarnings",
                     "--projection=o",
-                    "--view=axes,scales",
                     "--autocenter",
                     "--viewall",
                     "--camera", eye+",0,0,0"
                 ]
+                if "Edges" in extype:  # Force render
+                    scadcmd.extend(["--view=axes,scales,edges"])
+                else:
+                    scadcmd.extend(["--view=axes,scales"])
                 if "FR" in extype:  # Force render
                     scadcmd.extend(["--render", ""])
                 scadcmd.append(scriptfile)
@@ -174,12 +177,15 @@ class ImageProcessing(object):
                 "--imgsize={}".format(imgsizes[0]),
                 "--hardwarnings",
                 "--projection=o",
-                "--view=axes,scales",
                 "--autocenter",
                 "--viewall"
             ]
             if "2D" in extype:  # 2D viewpoint
                 scadcmd.extend(["--camera", "0,0,0,0,0,0,500"])
+            if "Edges" in extype:  # Force render
+                scadcmd.extend(["--view=axes,scales,edges"])
+            else:
+                scadcmd.extend(["--view=axes,scales"])
             if "FR" in extype:  # Force render
                 scadcmd.extend(["--render", ""])
             scadcmd.append(scriptfile)
diff --git a/shapes.scad b/shapes.scad
index c61efe1..76d3a4c 100644
--- a/shapes.scad
+++ b/shapes.scad
@@ -779,7 +779,7 @@ module tube(
 	od=undef, od1=undef, od2=undef,
 	ir=undef, id=undef, ir1=undef,
 	ir2=undef, id1=undef, id2=undef,
-	center=undef, orient=ORIENT_Z, anchor=UP,
+	center=undef, orient=ORIENT_Z, anchor=BOTTOM,
 	realign=false
 ) {
 	r1 = first_defined([or1, od1/2, r1, d1/2, or, od/2, r, d/2, ir1+wall, id1/2+wall, ir+wall, id/2+wall]);
@@ -1128,7 +1128,7 @@ module pie_slice(
 	ang=30, l=undef,
 	r=10, r1=undef, r2=undef,
 	d=undef, d1=undef, d2=undef,
-	orient=ORIENT_Z, anchor=UP,
+	orient=ORIENT_Z, anchor=BOTTOM,
 	center=undef, h=undef
 ) {
 	l = first_defined([l, h, 1]);
@@ -1263,9 +1263,9 @@ module slot(
 //   center = If given and true, centers vertically.  If given and false, drops flush with XY plane.  Overrides `anchor`.
 //   $fn2 = The `$fn` value to use on the small round endcaps.  The major arcs are still based on `$fn`.  Default: `$fn`
 //
-// Example: Typical Arced Slot
+// Example(Med): Typical Arced Slot
 //   arced_slot(d=60, h=5, sd=10, sa=60, ea=280);
-// Example: Conical Arced Slot
+// Example(Med): Conical Arced Slot
 //   arced_slot(r=60, h=5, sd1=10, sd2=15, sa=45, ea=180);
 module arced_slot(
 	r=undef, d=undef, h=1.0,
diff --git a/sliders.scad b/sliders.scad
index 667555a..f7f706e 100644
--- a/sliders.scad
+++ b/sliders.scad
@@ -29,7 +29,7 @@
 //   anchor = Alignment of the slider.  Use the constants from `constants.scad`.  Default: `UP`.
 // Example:
 //   slider(l=30, base=10, wall=4, slop=0.2, orient=ORIENT_Y);
-module slider(l=30, w=10, h=10, base=10, wall=5, ang=30, slop=PRINTER_SLOP, orient=ORIENT_Y, anchor=UP)
+module slider(l=30, w=10, h=10, base=10, wall=5, ang=30, slop=PRINTER_SLOP, orient=ORIENT_Y, anchor=BOTTOM)
 {
 	full_width = w + 2*wall;
 	full_height = h + base;
@@ -37,18 +37,18 @@ module slider(l=30, w=10, h=10, base=10, wall=5, ang=30, slop=PRINTER_SLOP, orie
 	orient_and_anchor([full_width, l, h+2*base], orient, anchor, orig_orient=ORIENT_Y, chain=true) {
 		down(base+h/2) {
 			// Base
-			cuboid([full_width, l, base-slop], chamfer=2, edges=edges([FRONT,BACK], except=BOT), anchor=UP);
+			cuboid([full_width, l, base-slop], chamfer=2, edges=edges([FRONT,BACK], except=BOT), anchor=BOTTOM);
 
 			// Wall
 			xflip_copy(offset=w/2+slop) {
-				cuboid([wall, l, full_height], chamfer=2, edges=edges(RIGHT, except=BOT), anchor=UP+RIGHT);
+				cuboid([wall, l, full_height], chamfer=2, edges=edges(RIGHT, except=BOT), anchor=BOTTOM+LEFT);
 			}
 
 			// Sliders
 			up(base+h/2) {
 				xflip_copy(offset=w/2+slop+0.02) {
 					bev_h = h/2*tan(ang);
-					prismoid([l, h], [l-w, 0], h=bev_h+0.01, orient=ORIENT_XNEG, anchor=LEFT);
+					prismoid([l, h], [l-w, 0], h=bev_h+0.01, orient=ORIENT_XNEG, anchor=RIGHT);
 				}
 			}
 		}
@@ -73,7 +73,7 @@ module slider(l=30, w=10, h=10, base=10, wall=5, ang=30, slop=PRINTER_SLOP, orie
 //   anchor = Alignment of the rail.  Use the constants from `constants.scad`.  Default: `UP`.
 // Example:
 //   rail(l=100, w=10, h=10);
-module rail(l=30, w=10, h=10, chamfer=1.0, ang=30, orient=ORIENT_Y, anchor=UP)
+module rail(l=30, w=10, h=10, chamfer=1.0, ang=30, orient=ORIENT_Y, anchor=BOTTOM)
 {
 	attack_ang = 30;
 	attack_len = 2;
@@ -99,7 +99,7 @@ module rail(l=30, w=10, h=10, chamfer=1.0, ang=30, orient=ORIENT_Y, anchor=UP)
 	y1 = l/2;
 	y2 = y1 - attack_len * cos(attack_ang);
 
-	orient_and_anchor([w, l, h], orient, anchor, orig_orient=ORIENT_Y, chain=true) {
+	orient_and_anchor([w, h, l], orient, anchor, orig_orient=ORIENT_Y, chain=true) {
 		polyhedron(
 			convexity=4,
 			points=[
diff --git a/threading.scad b/threading.scad
index 50a003a..47b0e18 100644
--- a/threading.scad
+++ b/threading.scad
@@ -97,7 +97,7 @@ module thread_helix(base_d, pitch, thread_depth=undef, thread_angle=15, twist=72
 //   trapezoidal_threaded_rod(d=10, l=40, pitch=3, thread_angle=15, left_handed=true, starts=3, $fn=36);
 //   trapezoidal_threaded_rod(d=25, l=40, pitch=10, thread_depth=8/3, thread_angle=50, starts=4, center=false, $fa=2, $fs=2);
 //   trapezoidal_threaded_rod(d=50, l=35, pitch=8, thread_angle=30, starts=3, bevel=true);
-//   trapezoidal_threaded_rod(l=25, d=10, pitch=2, thread_angle=15, starts=3, $fa=1, $fs=1, orient=ORIENT_X, anchor=UP);
+//   trapezoidal_threaded_rod(l=25, d=10, pitch=2, thread_angle=15, starts=3, $fa=1, $fs=1, orient=ORIENT_X, anchor=BOTTOM);
 module trapezoidal_threaded_rod(
 	d=10,
 	l=100,
@@ -872,7 +872,7 @@ module pco1881_neck(wall=2, orient=ORIENT_Z, anchor="support-ring")
 //   "inside-top" = Centered on the inside top of the cap.
 // Example:
 //   pco1881_cap();
-module pco1881_cap(wall=2, orient=ORIENT_Z, anchor=TOP)
+module pco1881_cap(wall=2, orient=ORIENT_ZNEG, anchor=BOTTOM)
 {
 	$fn = segs(33/2);
 	w = 28.58 + 2*wall;
diff --git a/walls.scad b/walls.scad
index 3e6cb38..27b0c52 100644
--- a/walls.scad
+++ b/walls.scad
@@ -33,7 +33,7 @@
 //
 // Example:
 //   narrowing_strut(w=10, l=100, wall=5, ang=30);
-module narrowing_strut(w=10, l=100, wall=5, ang=30, orient=ORIENT_Y, anchor=FRONT)
+module narrowing_strut(w=10, l=100, wall=5, ang=30, orient=ORIENT_Y, anchor=BOTTOM)
 {
 	h = wall + w/2/tan(ang);
 	size = [w, h, l];