cf https://en.wikipedia.org/wiki/ARRA_(computer)

As a connection to modern times, GvR was at the CWI when he developed Python.

Also, Dijkstra was at the “Mathematisch Centrum” when the ARRA was being designed, and wrote agoutis design and software (https://www.cs.utexas.edu/users/EWD/indexMCreps.html)

It was a 30-bit machine with 1,024 words and 2 registers, with 2 instructions per word.