Animated delta bot (Q43866)

Inspired by http://www.thingiverse.com/thing:5998 . Unfortunately, can not be made as-is. Hence the work-in-progress... This is an OpenSCAD design suitable for experimenting with a deltabot with various arm lengths. The main parameters (base width, arm length, animation toolpath etc) can be changed on the fly. It serves me as a test of both the coordinate transformation math and the resulting practical reach for a given arm configuration. Parts of it can be reused in other designs, for example the 3d line and toolpath rendering.