Uh... Well you've got a bunch of long flat blocks that you stack up in layers of three, so three like this [He holds out three fingers in a group.] then three across those [He holds three fingers of his other hand above and perpendicular to the other set of fingers.] and then keep going until you've got a tower. [He swaps the positions of the groups of fingers a few times, miming stacking them up.] Then the players take turns trying to take a block from the middle of the tower and putting it on top without the tower falling down. Whoever makes it fall down is the loser.