So I’m doing this problem, and so far I’ve only deduced that a move is floor dividing all the rock piles by a certain number then subtracting one from any one of them.

However, I don’t know where to go from here. Usually in the (rather few) game theory problems I’ve seen, one can “match” the moves another does to guarantee a win. However, I don’t know how Bessie could “match” Elsie in this game.

if i’m understanding the problem statement correctly, it is saying a move is where a player picks a number if at least one of the piles has at least that many stones, then that number is removed from a chosen pile. The next cow can only choose a number that is a multiple of the previous.

Yes- I said that that was *equivalent* to floor dividing all the rock piles by a certain number then subtracting one from any one of them.