PiCTeX is a TeX macro package developed by Michael Wichura which allows diagrams and drawing to be created using TeX. It is freely available on the web (hunt a bit using a search engine and archives containing it will quickly be found). The rub is that no documentation for PiCTeX seems to be available anywhere on the web. (There is a manual by Michael Wichura which is available but it is not free.) With a great deal of hunting, I located a lovely bit of C code by Sergey Bagdasarov. His C program creates a (rather elaborate) PiCTeX file that shows plots of splines (special curves used to model things). I was able to compile and run his program, which provided me with the only example of an actual PiCTeX file I could find anywhere on the web. From that I was able to see how at least a little PiCTeX code works.
Here, therefore, is my example of PiCTeX
code. This example should produce a right triangle with its three vertices
labelled A, B and C. (To compile a PiCTeX and
view the results, the PiCTeX macro file pictex.tex should be downloaded
off the web and put in the same directory as the PiCTeX file you wish to
compile. At least, that worked for me. I used PCTeX v. 4 on
a Windows 95 machine.) Undoubtedly, if I ever do get the PiCTeX manual,
I will be able to make full and effective use of PiCTeX.