UK, 2 pounds, 1997.

The reverse design of this standard circulation two pound coin represents technology through the ages. The central area symbolises the Iron Age and features decorative whorls that are familiar from ancient Celtic Art. Moving outwards from the centre, the second ring, with its series of cogs and wheels, represents the Industrial Revolution, which is said to have started in Britain. The third ring depicts the silicon chip, that symbol of the computer age and the technological revolution. Finally, at the edge of the coin, we see a symbolic representation of the Internet.

The design of this coin infamously contains an error: there are 19 gears in the cogwheel. An odd number of gears would not turn; only an even number of gears would work.