descriptive geometry



Years ago i developed a teaching unit on some aspects of   
descriptive geometry with MuPAD.
http://www.hattendoerfer.de/friedrich/anageo/anageo.html
(sorry only in german)

I hadn't realizes all planed items.

Now i want to do the same with wxmaxima/gnuplot

My Question:

Are there already links to
- hidden lines
- coloring areas?  


-- 
mit freundlichen Gr??en
Friedrich Hattendorf

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Lernen ist wie das Rudern gegen den Strom;
sobald man aufh?rt, treibt man zur?ck
Benjamin Britten