3 or 4?

Tree-wheel carriage.
Three-wheel carriage in Francr, 1828-1855.

Hardly anyone would think over how many wheels should be there on the cart: 3 or 4? Definitely 4! But the French preferred 3 wheels on a cart in 19th century. Between 1828 and 1855 owners of three-wheeled carriages avoided taxes which were applied to four-wheeled carriages only.