... casually replied, I d rather play a matchstick puzzle - a childhood game where you move matchsticks to fix a math equation. Then I said, half-jokingly, Why not create an online version for free? I had already built @Trangram , so I figured a small puzzle game would be easy. That night, while lying in bed, I started thinking about building a solver that could generate and solve matchstick puzzles automatically. My mind became so active I couldn't sleep. (Trust ... ... equation. This keeps the focus on solving puzzles, and it also makes the UI much cleaner. Next came game flow, UI, and sound effects. I'm obsessed with clean, clear, responsive interfaces, just like how I designed @Trangram