Body construction Monocoque with front and rear crumple zones and removable hardtop. Those interior crumple zones decelerate a sled-mounted survival cell. Modern theories of vehicle crashworthiness point in the opposite direction, towards vehicles that crumple progressively. The folded limestone strata known as the "Lulworth crumple" are particularly visible at Stair Hole. The Smart Fortwo uses a very small front crumple zone. As the guards attempt to pull the embracing skeletons apart, they both crumple into dust. The flat front of the Omni also prevented the addition of crumple zones. The result is a larger front crumple zone. Previously, the character would simply crumple into a heap. When replacing the booklet, it can get snagged and crumple or rip. The HD thrust system makes the opponent hit the wall and crumple for follow-up attacks.