ELI5: Explain Like I'm 5

PGF/TikZ

pgf/tikz is a tool used to create pictures with mathematical formulas. It is used by mathematicians, scientists and teachers to make pictures out of complicated formulas and equations. It can be used to draw shapes, diagrams, graphs and other types of pictures. Tikz works by giving instructions to the computer about what shapes and lines to draw. It is a very useful tool for visualizing complicated mathematical concepts.