If this kind of thing amuses you can buy a purely mechanical implementation called either Braino or Dr. Nim for about £10. Here's a video on the subject from Ma

If this kind of thing amuses you can buy a purely mechanical implementation called either Braino or Dr. Nim for about £10. Here's a video on the subject from Matt Parker @ Standup Maths. https://www.youtube.com/watch?v=9KABcmczPdg https://www.youtube.com/watch?v=9KABcmczPdg