Amusingly, I made the same thing late last year, though just on an ordinary computer, allowing you to draw in the browser. I used pageflip [0] with styling akin to Riddle's actual diary and a tiny local model crafted for roleplay via ollama. I remember writing "my name is Harry Potter, what is yours?" and getting back Snape, Malfoy, and even Harry Potter back across a number of iterations. After completing my experiment I learned I wasn't the first to think of this idea and found a few other similar AI Riddle diaries out there.

Incidentally, I have a Remarkable 2 and as of this weekend an m4 iPad air. Maybe I'll test this one out and see what the landscape for running models on iOS looks like.

0) https://nodlik.github.io/react-pageflip/