The final model should be a 50mm x 50mm (or smaller) Simon Says game based on the ATtiny85 that can be used as a key chain. The plan is to have a rechargeable 500mAh LiPo battery with integrated LiPo charger and USB that can also be used to upload code through a boot loader.
The schematic and PCB are made using KiCAD.
All of the project files are available on GitHub so feel free to take a look or fork the project and make your own variant.
Nice one. How's it supposed to be programmed, though?