To keep the lid of a MacBook Pro (Early 2008, pre-Unibody, 17") open at a specific angle. If the laptop is tilted forward -- such as when the user is lying down, knees bent, with the laptop on lap -- the weight of the screen tends to close it. This model wedges it open.

This version adds a second wedge to spread the load to both sides, and makes it all a bit looser by making the base and lid a little thicker.