Chess for Numworks calculators. The engine is an early version of gnuchess (2.0) as found in the Rockbox firmware. Chess pieces are the Lichess Meastro theme pieces as found in the Pychess code base.
You can upload the nwa file from the release page to your calculator on my.numworks.com/apps.
Arrow to move the selection cursor, ok to confirm selection and make moves. Back switches sides. +/- to select play level. Ans forces a computer move. Exe starts a new game.