diff --git a/affine.scad b/affine.scad
index f5ecdd9..422ee1f 100644
--- a/affine.scad
+++ b/affine.scad
@@ -259,6 +259,49 @@ function affine3d_rot_from_to(from, to) = let(
 ];
 
 
+// Function: affine_frame_map()
+// Usage: map = affine_frame_map(x=v1,y=v2);
+//        map = affine_frame_map(x=v1,z=v2);
+//        map = affine_frame_map(y=v1,y=v2);
+//        map = affine_frame_map(v1,v2,v3);
+// Description:
+//   Returns a transformation that maps one coordinate frame to another.  You must specify two or three of `x`, `y`, and `z`.  The specified
+//   axes are mapped to the vectors you supplied.  If you give two inputs, the third vector is mapped to the appropriate normal to maintain a right hand coordinate system.  
+//   If the vectors you give are orthogonal the result will be a rotation.  The `reverse` parameter will supply the inverse map, which enables you
+//   to map two arbitrary coordinate systems two each other by using the canonical coordinate system as an intermediary.
+// Arguments:
+//   x = Destination vector for x axis
+//   y = Destination vector for y axis
+//   z = Destination vector for z axis
+//   reverse = reverse direction of the map.  Default: false
+// Examples:
+//   T = affine_frame_map(x=[1,1,0], y=[-1,1]);   // This map is just a rotation around the z axis
+//   T = affine_frame_map(x=[1,0,0], y=[1,1]);    // This map is not a rotation because x and y aren't orthogonal
+//                  // The next map sends [1,1,0] to [0,1,1] and [-1,1,0] to [0,-1,1]
+//   T = affine_frame_map(x=[0,1,1], y=[0,-1,1]) * affine_frame_map(x=[1,1,0], y=[-1,1,0],reverse=true);
+function affine_frame_map(x,y,z, reverse=false) =
+  assert(num_defined([x,y,z])>=2, "Must define at least two inputs")
+  let(
+    xvalid = is_undef(x) || (is_vector(x) && len(x)==3),
+    yvalid = is_undef(y) || (is_vector(y) && len(y)==3),
+    zvalid = is_undef(z) || (is_vector(z) && len(z)==3)
+  )
+  assert(xvalid,"Input x must be a length 3 vector")
+  assert(yvalid,"Input y must be a length 3 vector")
+  assert(zvalid,"Input z must be a length 3 vector")
+  let(
+    x = is_def(x) ? normalize(x) : undef,
+    y = is_def(y) ? normalize(y) : undef,    
+    z = is_def(z) ? normalize(z) : undef,    
+    map = is_undef(x) ? [cross(y,z), y, z] :
+          is_undef(y) ? [x, cross(z,x), z] :
+          is_undef(z) ? [x, y, cross(x,y)] :
+                        [x, y, z]
+  )
+  reverse ? affine2d_to_3d(map) : affine2d_to_3d(transpose(map));
+
+
+
 // Function: affine3d_mirror()
 // Usage:
 //   mat = affine3d_mirror(v);
@@ -441,4 +484,7 @@ function is_2d_transform(t) =    // z-parameters are zero, except we allow t[2][
   (t[2][2]==1 || !(t[0][0]==1 && t[0][1]==0 && t[1][0]==0 && t[1][1]==1));   // But rule out zscale()
 
 
+
+
+
 // vim: noexpandtab tabstop=4 shiftwidth=4 softtabstop=4 nowrap
diff --git a/skin.scad b/skin.scad
index f9c4abc..3ca4fb2 100644
--- a/skin.scad
+++ b/skin.scad
@@ -779,46 +779,6 @@ module sweep(shape, transformations, closed=false, caps, convexity=10) {
   vnf_polyhedron(sweep(shape, transformations, closed, caps), convexity=convexity);
 }  
 
-// Function: affine_frame_map()
-// Usage: map = affine_frame_map(x=v1,y=v2);
-//        map = affine_frame_map(x=v1,z=v2);
-//        map = affine_frame_map(y=v1,y=v2);
-//        map = affine_frame_map(v1,v2,v3);
-// Description:
-//   Returns a transformation that maps one coordinate frame to another.  You must specify two or three of `x`, `y`, and `z`.  The specified
-//   axes are mapped to the vectors you supplied.  If you give two inputs, the third vector is mapped to the appropriate normal to maintain a right hand coordinate system.  
-//   If the vectors you give are orthogonal the result will be a rotation.  The `reverse` parameter will supply the inverse map, which enables you
-//   to map two arbitrary coordinate systems two each other by using the canonical coordinate system as an intermediary.
-// Arguments:
-//   x = Destination vector for x axis
-//   y = Destination vector for y axis
-//   z = Destination vector for z axis
-//   reverse = reverse direction of the map.  Default: false
-// Examples:
-//   T = affine_frame_map(x=[1,1,0], y=[-1,1]);   // This map is just a rotation around the z axis
-//   T = affine_frame_map(x=[1,0,0], y=[1,1]);    // This map is not a rotation because x and y aren't orthogonal
-//                  // The next map sends [1,1,0] to [0,1,1] and [-1,1,0] to [0,-1,1]
-//   T = affine_frame_map(x=[0,1,1], y=[0,-1,1]) * affine_frame_map(x=[1,1,0], y=[-1,1,0],reverse=true);
-function affine_frame_map(x,y,z, reverse=false) =
-  assert(num_defined([x,y,z])>=2, "Must define at least two inputs")
-  let(
-    xvalid = is_undef(x) || (is_vector(x) && len(x)==3),
-    yvalid = is_undef(y) || (is_vector(y) && len(y)==3),
-    zvalid = is_undef(z) || (is_vector(z) && len(z)==3)
-  )
-  assert(xvalid,"Input x must be a length 3 vector")
-  assert(yvalid,"Input y must be a length 3 vector")
-  assert(zvalid,"Input z must be a length 3 vector")
-  let(
-    x = is_def(x) ? normalize(x) : undef,
-    y = is_def(y) ? normalize(y) : undef,    
-    z = is_def(z) ? normalize(z) : undef,    
-    map = is_undef(x) ? [cross(y,z), y, z] :
-          is_undef(y) ? [x, cross(z,x), z] :
-          is_undef(z) ? [x, y, cross(x,y)] :
-                        [x, y, z]
-  )
-  reverse ? affine2d_to_3d(map) : affine2d_to_3d(transpose(map));
 
 // Function&Module: path_sweep()
 // Usage: path_sweep(shape, path, [method], [normal], [closed], [twist], [twist_by_length], [symmetry], [last_normal], [tangent], [relaxed], [caps], [convexity], [transforms])