1974 – Square-Wheeled Bicycle – (Japanese)
No, not a bumpy ride. Most likely a cam similar to the "Square Wheel" rides on the swingarm and driven by the main pedal crank. This vehicle was submitted by an employee to the All-Honda Idea Contest in Japan in 1974. Source: Popular Science, Aug 1974.
See other Walking Wheels at the bottom of the Walking Machines page.