I've wanted to build something pretty distantly adjacent to this for real-world spaced repetition cards. Have a deck of 3x5 cards, with qr codes at one corner.

I've wanted to build something pretty distantly adjacent to this for real-world spaced repetition cards. Have a deck of 3x5 cards, with qr codes at one corner. Dump the deck into your scanner (like a money counter) and it splits the deck, giving you a pile of the cards you should review today. Then you switch the scanner into "trying to remember" mode, and you put the cards you successfully recalled into one slot, and the ones you failed into another. The scanner reads their QR codes, notes that you succeeded/failed, so it can updated spacing windows for the next run.