http://partiallydisassembled.net/euclid.html

Thought I'd jump into the 2D vector fun fest with my own sacrificial 
module.  This one does the usual 2D and 3D vector, matrix and quaternion 
operations.  It also has classes for 2D and 3D points, lines, rays, line 
segments, circles and spheres, and routines for finding the nearest 
points, distances and intersections between any two of those.

There is comprehensive documentation on the website but no runnable 
examples outside of the doctests yet.

Some work to be done (planes, boxes and rectangles spring to mind), but 
I'm following the "release early" mantra today, so you get a 
cookie-dough view of the baking process.

Alex.