Dr NIM game
The classic DrNIM game now to print in 3d.
http://www.cs.miami.edu/home/burt/learning/Csc427.152/491_Dr-Nim-Manual5b15d.pdf
It is an exact copy of the classic game but on a smaller scale so that it can be printed from one piece. all parts have 20% fill and two outer layers. except the "balancinr" and "tope" parts which are 100% fill.
You need 20 8mm steel ball, 15 for the game and 5 for the counterweights. and for the shafts you need 2mm wire
https://www.youtube.com/watch?v=xGnvYjFP7JA&ab_channel=GabrielDIY
Now I have made a bigger version that is printed in four pieces, and works much better as the mechanism is stronger and heavier. https://www.thingiverse.com/thing:3574274