At one time in England, houses were taxed not by square footage, but instead by how many windows they had! To avoid taxes, people removed and bricked up some of their windows. You can still see these mismatched sections of brick when you walk around today!

Also in Britain, a tax on bricks was levied to fund the war against American independence. What's a bricklayer to do? Why, use bigger bricks of course! You can apparently tell if a building dates to before or after the revolutionary war based on the size of the bricks.

The measurement of cargo ships (sailing) for taxation also had an effect on ship design. In Britain, the formula was taxable tonnage = ((Length - 3/5 breadth) * (1/2 breadth)^2) / 94. The American system was ((length - 3/5 breadth) * breadth * depth) / 94 , with the depth being statutorily defined as half of the breadth. In both countries the breadth was measured on deck. A long narrow ship leaving an American port would often find itself measured twice as heavy when it arrived in England! As a result of these definitions, ships tended to be deeper than was optimal for best sailing in order to store more cargo in the untaxed area below the line where the formula defined the bottom. British ships, in particular, often had a pronounced tumble home (where the deck is not the widest part of the ship - usually the hull slopes inwards from the waterline up to the deck).

Tax avoidance is fascinating!