There are many, many tools for producing pictures for mathematics exposition. The one that I am going to describe is something I developed for myself because I wasn't happy with what the other tools had to offer.

It is a Python interface to PostScript, the programming language used by printers. Python is a programming language that was developed about 15 years ago, and it has recently become quite popular. It is an interpreted language, so you just run a program by running Python on the program file itself, or possibly making the program file an executable. I call my package PiScript.