Knot-style Parametric Function Script ( Python )

In my ongoing quest to eliminate or supersede all things Matlab, I present a functional solution to the problem of extruding along arbitrary contours, written in python.

This is a reaction to http://www.thingiverse.com/thing:7080, itself a derivative of http://www.thingiverse.com/thing:6923. Credit to both these authors for the concept and motivation.

Parameters are specified at the top of the script. A closed curve in 3D is specified as f:t→(x,y,z) a parametric function of t. A closed