Re: [math-fun] Computer Algebra Systems [meta]

I'll toss in a mention of a geometric algebra system: http://www.geometryexpressions.com/ It has a powerful constraint system, and updates constructions algebraically on the fly. If you write to them with a good story, and promise to post some of your constructions publicly, you can get a good deal on the price. (Sending a good story to either Wolfram Research or Maplesoft also gets a good discount, I've learned from experience.). Ed Pegg Jr