Elliott 903 Simulator by Andrew Herbert.
If you go into the bin/release
directory you’ll find a series of folders named after various Elliott languages and apps. In each of these you’ll find filed with names like DEMO3.DAT.
So run in release mode, then
CD folder
DO DEMOx
should run a demo for you.
The 903ALGOL folder is probably the most interesting. Some of the later demos pop up windows to represent line printer and graph plotter output.
(As I’m doing this from memory you might have to poke around a bit to find the demo folders...)
Andrew