The wheel is good for keeping your victim still during the procedure. They can be bound around the circumference or simply strechted across, tying limbs to the spokes and rim. All tools are, by this point, useful and you may administer the torture in any way you like. But the forte of the wheel is the gaps. When you have decided that the victim shall die you can smash the limbs with a hammer, making them fold in beetween the frame.