A small "clock" that can be run on a Ti-Nspire calculator.
The thing can be emulated via the Firebird Emulator, but you'll need to dump a bunch of firmware files which I cannot provide for obvious reasons.
The original clock also had animations for time left within the lesson, time left until next break & time left until end of school day, but I cannot find that version anymore.
I soft-bricked my calculator a bunch of times while trying to run Linux on it and I must have lost that version during one of the attempts :(