Added code from the openscad svn repo for easy use and improvement.

boxes.scad

@@ -0,0 +1,43 @@
+// Library: boxes.scad
+// Version: 1.0
+// Author: Marius Kintel
+// Copyright: 2010
+// License: BSD
+
+// roundedBox([width, height, depth], float radius, bool sidesonly);
+
+// EXAMPLE USAGE:
+// roundedBox([20, 30, 40], 5, true);
+
+// size is a vector [w, h, d]
+module roundedBox(size, radius, sidesonly)
+{
+  rot = [ [0,0,0], [90,0,90], [90,90,0] ];
+  if (sidesonly) {
+    cube(size - [2*radius,0,0], true);
+    cube(size - [0,2*radius,0], true);
+    for (x = [radius-size[0]/2, -radius+size[0]/2],
+           y = [radius-size[1]/2, -radius+size[1]/2]) {
+      translate([x,y,0]) cylinder(r=radius, h=size[2], center=true);
+    }
+  }
+  else {
+    cube([size[0], size[1]-radius*2, size[2]-radius*2], center=true);
+    cube([size[0]-radius*2, size[1], size[2]-radius*2], center=true);
+    cube([size[0]-radius*2, size[1]-radius*2, size[2]], center=true);
+
+    for (axis = [0:2]) {
+      for (x = [radius-size[axis]/2, -radius+size[axis]/2],
+             y = [radius-size[(axis+1)%3]/2, -radius+size[(axis+1)%3]/2]) {
+        rotate(rot[axis])
+          translate([x,y,0])
+          cylinder(h=size[(axis+2)%3]-2*radius, r=radius, center=true);
+      }
+    }
+    for (x = [radius-size[0]/2, -radius+size[0]/2],
+           y = [radius-size[1]/2, -radius+size[1]/2],
+           z = [radius-size[2]/2, -radius+size[2]/2]) {
+      translate([x,y,z]) sphere(radius);
+    }
+  }
+}

shapes.scad

@@ -0,0 +1,135 @@
+/*
+ *  OpenSCAD Shapes Library (www.openscad.org)
+ *  Copyright (C) 2009  Catarina Mota
+ *
+ *  License: LGPL 2.1 or later
+*/
+
+
+//box(width, height, depth);
+//roundedBox(width, height, depth, factor);
+//cone(height, radius);
+//oval(width, height, depth);
+//tube(height, radius, wall);
+//ovalTube(width, height, depth, wall);
+//hexagon(height, depth);
+//octagon(height, depth);
+//dodecagon(height, depth);
+//hexagram(height, depth);
+//rightTriangle(adjacent, opposite, depth);
+//equiTriangle(side, depth);
+//12ptStar(height, depth);
+
+//----------------------
+
+// size is a vector [w, h, d]
+module box(size) {
+  cube(size, true);
+}
+
+// size is a vector [w, h, d]
+module roundedBox(size, radius) {
+  cube(size - [2*radius,0,0], true);
+  cube(size - [0,2*radius,0], true);
+  for (x = [radius-size[0]/2, -radius+size[0]/2],
+       y = [radius-size[1]/2, -radius+size[1]/2]) {
+    translate([x,y,0]) cylinder(r=radius, h=size[2], center=true);
+  }
+}
+
+module cone(height, radius, center = false) {
+  cylinder(height, radius, 0, center);
+}
+
+module oval(w,h, height, center = false) {
+  scale([1, h/w, 1]) cylinder(h=height, r=w, center=center);
+}
+
+// wall is wall thickness
+module tube(height, radius, wall, center = false) {
+  difference() {
+    cylinder(h=height, r=radius, center=center);
+    cylinder(h=height, r=radius-wall, center=center);
+  }
+}
+
+// wall is wall thickness
+module ovalTube(height, rx, ry, wall, center = false) {
+  difference() {
+    scale([1, ry/rx, 1]) cylinder(h=height, r=rx, center=center);
+    scale([(rx-wall)/rx, (ry-wall)/rx, 1]) cylinder(h=height, r=rx, center=center);
+  }
+}
+
+// size is the XY plane size, height in Z
+module hexagon(size, height) {
+  boxWidth = size/1.75;
+  for (r = [-60, 0, 60]) rotate([0,0,r]) cube([boxWidth, size, height], true);
+}
+
+// size is the XY plane size, height in Z
+module octagon(size, height) {
+  intersection() {
+    cube([size, size, height], true);
+    rotate([0,0,45]) cube([size, size, height], true);
+  }
+}
+
+// size is the XY plane size, height in Z
+module dodecagon(size, height) {
+  intersection() {
+    hexagon(size, height);
+    rotate([0,0,90]) hexagon(size, height);
+  }
+}
+
+// size is the XY plane size, height in Z
+module hexagram(size, height) {
+  boxWidth=size/1.75;
+  for (v = [[0,1],[0,-1],[1,-1]]) {
+    intersection() {
+      rotate([0,0,60*v[0]]) cube([size, boxWidth, height], true);
+      rotate([0,0,60*v[1]]) cube([size, boxWidth, height], true);
+    }
+  }
+}
+
+module rightTriangle(adjacent, opposite, height) {
+  difference() {
+    translate([-adjacent/2,opposite/2,0]) cube([adjacent, opposite, height], true);
+    translate([-adjacent,0,0]) {
+      rotate([0,0,atan(opposite/adjacent)]) dislocateBox(adjacent*2, opposite, height);
+    }
+  }
+}
+
+module equiTriangle(side, height) {
+  difference() {
+    translate([-side/2,side/2,0]) cube([side, side, height], true);
+    rotate([0,0,30]) dislocateBox(side*2, side, height);
+    translate([-side,0,0]) {
+      rotate([0,0,60]) dislocateBox(side*2, side, height);
+    }
+  }
+}
+
+module 12ptStar(size, height) {
+  starNum = 3;
+  starAngle = 360/starNum;
+  for (s = [1:starNum]) {
+    rotate([0, 0, s*starAngle]) cube([size, size, height], true);
+  }
+}
+
+//-----------------------
+//MOVES THE ROTATION AXIS OF A BOX FROM ITS CENTER TO THE BOTTOM LEFT CORNER
+//FIXME: Why are the dimensions changed?
+// why not just translate([0,0,-d/2]) cube([w,h,d]);
+module dislocateBox(w,h,d) {
+  translate([w/2,h,0]) {
+    difference() {
+      cube([w, h*2, d+1]);
+      translate([-w,0,0]) cube([w, h*2, d+1]);
+    }
+  }
+}

triangles.scad

@@ -16,7 +16,7 @@
  * @param number depth How wide/deep the triangle is in the 3rd dimension
  */
 /*
-module triangle(o_len, a_len, depth)
+module triangle_old(o_len, a_len, depth)
 {
 	difference()
 	{
@@ -51,5 +51,5 @@ module triangle(o_len, a_len, depth)
     }
 }
 
-triangle(5,10,7);
+//triangle(5,10,7);