While trying to build a pocket operator clone for the playdate, my son asked me if I could do a game for him.
My first attempt was an incremental game that allows him to just turn the crank and see the number going up.
Second attempt is CountingMad, a "game" to solve simple math problems.
After the game was done and while browsing the "not-actually-games" category I saw Robert's basically counting and asked if he would open source the dial since it was so enjoyable, both sound and visuals.
For now it's only additions and subtractions since that's what he is learning. Maybe I'll add more operations with time.