Who: I adapted existing attiny25/85 charlieplexed LED circuitry/code to the attiny45. Yoyo model from friend Laura Shumaker.
Details: 6 charlieplexed LEDs on 3 pins on an Attiny45, leaving pins for a button (on/off) and a phototransistor (for receiving new images to display). Intended to be press-fit into a (here 3d-printed) yoyo body with a depressible thermoformed cover and a coin-cell battery.