Educational gear cutting

Educational gear cutting
Gears are usually made milling with a tool. The the gear in this project is created by virtual milling with a virtual tool. (As opposed to the standard gear creation in CAD programs that directly extrude a gear that is calculated by formulas).

The attached file is written in Lua that can be interpreted and rendered by IceSL. It's not compatible to OpenSCAD (IceSL renderes in real-time, there are no extra buttons to preview or render). It produces an involute gear, with a few steps:
-Prepare a raw cylinder to be milled (blank, not rendered per default, color red)
-Prepare the milling tool, a trapezoid (Tool, raw)
-Prepare a shifted tool (Tool, shifted)
-Prepare a complex tool (Tool, complex)
-Display the gear

The 'raw' tool would be very thin, and it would be moved perpendicular to the cylinder, cutting two tooth flanks at once. These flanks would have the exact same shape as the tool, i.e. they would be straight. Additionally the cylinder is rotated