diff --git a/scripts/make_all_docs.sh b/scripts/make_all_docs.sh
index 8563cdd..0fad6f0 100755
--- a/scripts/make_all_docs.sh
+++ b/scripts/make_all_docs.sh
@@ -3,7 +3,7 @@
 if [[ $# > 0 ]]; then
     PREVIEW_LIBS="$@"
 else
-    PREVIEW_LIBS="compat attachments math arrays vectors matrices coords geometry triangulation quaternions hull constants transforms primitives shapes masks paths beziers metric_screws threading involute_gears sliders joiners linear_bearings nema_steppers wiring phillips_drive torx_drive debug"
+    PREVIEW_LIBS="compat attachments math arrays vectors matrices coords geometry triangulation quaternions hull constants transforms primitives shapes masks paths beziers walls metric_screws threading involute_gears sliders joiners linear_bearings nema_steppers wiring phillips_drive torx_drive debug"
 fi
 
 dir="$(basename $PWD)"
diff --git a/shapes.scad b/shapes.scad
index 67521c7..6e5ebf9 100644
--- a/shapes.scad
+++ b/shapes.scad
@@ -1260,8 +1260,7 @@ module slot(
 	r1 = get_radius(r1=r1, r=r, d1=d1, d=d, dflt=5);
 	r2 = get_radius(r1=r2, r=r, d1=d2, d=d, dflt=5);
 	sides = quantup(segs(max(r1, r2)), 4);
-	// TODO: implement orient and anchor.
-	// TODO: implement anchors.
+	// TODO: implement orient and anchors.
 	hull() spread(p1=p1, p2=p2, l=l, n=2) cyl(l=h, r1=r1, r2=r2, center=true, $fn=sides);
 }
 
@@ -1276,22 +1275,22 @@ module slot(
 //   arced_slot(h, r|d, sr1|sd1, sr2|sd2, [sa], [ea], [orient], [anchor|center], [$fn2]);
 //
 // Arguments:
-//   cp = centerpoint of slot arc. (default: [0, 0, 0])
-//   h = height of slot arc shape. (default: 1.0)
-//   r = radius of slot arc. (default: 0.5)
-//   d = diameter of slot arc. (default: 1.0)
-//   sr = radius of slot channel. (default: 0.5)
-//   sd = diameter of slot channel. (default: 0.5)
-//   sr1 = bottom radius of slot channel cone. (use instead of sr)
-//   sr2 = top radius of slot channel cone. (use instead of sr)
-//   sd1 = bottom diameter of slot channel cone. (use instead of sd)
-//   sd2 = top diameter of slot channel cone. (use instead of sd)
-//   sa = starting angle. (Default: 0.0)
-//   ea = ending angle. (Default: 90.0)
-//   orient = Orientation of the arced slot.  Use the `ORIENT_` constants from `constants.scad`.  Default: `ORIENT_Z`.
-//   anchor = Alignment of the arced slot.  Use the constants from `constants.scad`.  Default: `CENTER`.
-//   center = If true, centers vertically.  If 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
+//   cp = Centerpoint of slot arc.  Default: `[0, 0, 0]`
+//   h = Height of slot arc shape.  Default: `1`
+//   r = Radius of slot arc.  Default: `0.5`
+//   d = Diameter of slot arc.  Default: `1`
+//   sr = Radius of slot channel.  Default: `0.5`
+//   sd = Diameter of slot channel.  Default: `0.5`
+//   sr1 = Bottom radius of slot channel cone.  Use instead of `sr`.
+//   sr2 = Top radius of slot channel cone.  Use instead of `sr`.
+//   sd1 = Bottom diameter of slot channel cone.  Use instead of `sd`.
+//   sd2 = Top diameter of slot channel cone.  Use instead of `sd`.
+//   sa = Starting angle.  Default: `0`
+//   ea = Ending angle.  Default: `90`
+//   orient = Orientation of the arced slot.  Use the `ORIENT_` constants from `constants.scad`.  Default: `ORIENT_Z`
+//   anchor = Alignment of the arced slot.  Use the constants from `constants.scad`.  Default: `CENTER`
+//   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
 //   arced_slot(d=60, h=5, sd=10, sa=60, ea=280);
diff --git a/walls.scad b/walls.scad
index 5977c6b..bf77773 100644
--- a/walls.scad
+++ b/walls.scad
@@ -370,7 +370,7 @@ module thinning_triangle(h=50, l=100, thick=5, ang=30, strut=5, wall=3, diagonly
 module sparse_strut(h=50, l=100, thick=4, maxang=30, strut=5, max_bridge=20, orient=ORIENT_Y, anchor=CENTER)
 {
 	zoff = h/2 - strut/2;
-	yoff = l/2 - strut;
+	yoff = l/2 - strut/2;
 
 	maxhyp = 1.5 * (max_bridge+strut)/2 / sin(maxang);
 	maxz = 2 * maxhyp * cos(maxang);
@@ -397,8 +397,8 @@ module sparse_strut(h=50, l=100, thick=4, maxang=30, strut=5, max_bridge=20, ori
 			}
 			yspread(ystep, n=yreps) {
 				xspread(zstep, n=zreps) {
-					skew_xy(planar=true, ya=-ang) square([h-1.99*strut, strut], center=true);
-					skew_xy(planar=true, ya= ang) square([h-1.99*strut, strut], center=true);
+					skew_xy(planar=true, ya=-ang) square([(h-strut)/zreps, strut], center=true);
+					skew_xy(planar=true, ya= ang) square([(h-strut)/zreps, strut], center=true);
 				}
 			}
 		}