This is a second and a more direct implementation of Wythoff's Nim. To remind, the players take turns removing any number of objects from one of the heaps, or removing the same number of objects from the two heaps simultaneously.
In the applet objects are removed from the right. Click on the last square you want removed. If the box "Two heaps" is checked, the same number of objects will be removed from both heaps regardless of which one you click upon.