I was big into Yu-Gi-Oh! during high school. I had a lunch group I met with every day to duel in the school library and I have a lot of fond memories. Given how much I was playing at the time I needed a tool to track lifepoints, and given that smartphones weren't a thing at the time, and the fact that graphing calculators were required for school, my calculator was the obvious choice for to make this app for.

While none of what this app does is even remotely impressive, I used it daily and shared it with others in my dueling group. This was easily the most practical program I ever wrote for my TI 84 Plus.