In later years I've written text-based software for creating mathematically accurate diagrams in LaTeX and a miscellany of simple web-based programs for teaching concepts from algebra, geometry, and (pre-)calculus. I've also helped digitize public-domain math, physics, and astronomy books for Project Gutenberg.
"Hwang" rhymes with "song".
Q&A for people studying math at any level and professionals in related fields
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
Q&A for professional mathematicians