"Square wheel seems like a contradiction in terms, but this bicycle rides more smoothly than you might think. The secret is the shape of the road over which the wheels roll. The wheels can keep the bike moving in a straight line and at a constant velocity as long as it’s traveling over evenly spaced bumps of just the right shape, called an ‘inverted catenary’."
PS -Zé Pedro e Zicas, as rodas lembram-vos alguma coisa ? Eh!Eh!Eh!Eh!