As promised. You have to configure Maxima using Maxima-Init.mac in order for this to work right out of the box.
Without configuring Maxima you have to add a line at the top load("pw.lisp).
It is attached as a wxMaxima file.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Fourie Example 2.wxm
Type: application/octet-stream
Size: 2464 bytes
Desc: not available
Url : http://www.math.utexas.edu/pipermail/maxima/attachments/20080929/f0e10c95/attachment.obj