The 1824 Comet, designed by David Gordon, holds a unique position in automotive history as being probably the only vehicle not only to have three wheels, but also six feet. The rear two wheels supported the main weight of the vehicle, which was steered via the single front wheel, but none of the wheels were powered. Instead, a steam engine was used to power the feet, which propelled the vehicle forwards.
The Comet was braked by lifting the feet, which gradually brought it to a standstill, and it was steered by lifting the feet on one side or the other until the curve had been traversed.
- Pedrail wheelType of all-terrain wheel developed in the late 19th and early 20th centuries by Bramah Joseph Diplock.