The X12, by Chinese mobility company XSTO, is a complete re-think of the electric wheelchair.It features four independently-suspended wheels, each with their own electric motor, and a further ten motors that control the chair's disposition. It also features a unique tread system that allows the user to ascend stairs, albeit backwards.Descending stairs is done in a forward position.The tread system also comes into play in "caterpillar mode," which is used to traverse gaps that a regular wheelchair couldn't handle.The company says they're taking pre-orders and will launch the product later this year. Prices had not been announced at press time.