I personally only remember 8-queen puzzle. I tried google recently and it comes up with quite many applications. Basically anything that is likely to be solved

I personally only remember 8-queen puzzle. I tried google recently and it comes up with quite many applications. Basically anything that is likely to be solved by allowing free moving into wrong spot/position/thing to boost chances of being right and then at some point lowering the chance to form the solution. Well .. the name is self-described so I can't do it better than that.