I've written a clock program to run on an unexpanded Elf with PIXIE graphics. It proved to be quite a challenge to fit it into 256 bytes, but I've now got it working, with two bytes of RAM to spare. There are 12-hour and 24-hour versions. I've released it under the GPL 3.0 license.
The source code is in a github repository: https://github.com/brouhaha/elf-clock A text file containing instructions and hexadecimal object code is at: https://github.com/brouhaha/elf-clock/releases/download/v0.1/elf-clock-v0.1.txt