Then we found out how difficult using a tablet is for people with certain disabilities. Many things (like tap, double-tap, zoom-gesture) that we do automatically are (too) difficult. And many games/puzzles contain so much "clutter" on the screen, that people are lost and don't understand how to play the game.
So, I started with a project to create an Android app (on a tablet, as a phone screen is too small) with several easy-to-use games/puzzles. I cloned (and optimized!) some existing games and invented some new games. After many improvements, the app and the games/puzzles were good enough to share via the Google Play store. Because the games/puzzles deserve a larger audience than just the one person that started this development.
Now the app is in the Google Play store, the next challenge will be: promote the app, get in contact with people using the app, get feedback, and continuously improve/extend the app.