Would it be possible to make a vehicle that could transport an adult at, say, 10 mph yet fold up small enough to carry easily in one hand and weigh on the order of 10 pounds? Something like a miniature scooter with pedals instead of a board. It would need a handle that reached up to waist level or so. Its tires would have to be very small and its gear would have to be fairly high. The device would be useful for whenever you need to get somewhere quickly on foot, indoors or out. Instead of walking you'd just unfold the device and go twice as fast. The main problem in its design would probably be making it strong enough without making it too heavy.