Using two gym mats, the boys pretend to jump over a crevice flowing with hot lava. By degrees they increase the gap between the mats, increasing the danger and fun of the game. They increase the challenge to the maximum degree that still allows mastery. Once the mats reach that distance, the boys turn to other variations. They jump and roll to accentuate the feeling that the gap is wide and difficult to clear. A pretend lava ball hurls through space adding even more drama to the game. The boys create rules and apply strategies.