Hi everyone. I'm working on getting together some notes on school maths and of course I'd like to include some diagrams. The usual stuff, graphs of things like parabolas, circle geometry, etc. But I'm also skint. So I'm looking for some open source programs that can do that, and they need to be publication quality diagrams. I know about Sage, but I don't know Python and don't have the time to learn Python and Sage. I'm looking for a program that can do stuff like the following: http://www.mathillustrations.com/ http://geometryexpressions.com/ But those programs are seriously expensive. Any suggestions? Thanks.