Letter: Mint condition

Sir: The reverse side of the new pounds 2 coin depicts a circular train of 19 gear wheels. A circular gear-train will only work if it contains an even number of wheels. An odd number will "lock up". No matter how much effort is applied at any point in the system, the result will merely be a considerable amount of stress; the output will be zero.

One hopes the designer of the coin did not intend it to represent the British engineering industry.