The designer, Drew Spahn, was inspired by the ordeals of veterans of the wars in Iraq and Afghanistan who lost limbs and found themselves unable to engage in conventional skateboarding. His design, which he named Crosswing, won the Michelin Design Challenge focused on transportation.
The unit fits into a conventional prosthetic leg socket. The back of this “leg” folds out to create a four-wheeled skateboard. Lift up the heel for free movement, then lower it to engage the brake. The back leg rests on the back wheel for an experience that Spahn describes as a cross between riding a skateboard and a scooter.
-via Toxel