Just after the Second World War, Germans adopted cigarettes as a form of currency. This is an excellent form of money; it is almost impossible to forge. It is also very convenient, as it comes in clear denominations of a cigarette, a packet, and a carton. Money that comes in such denominations is easy to count. Most importantly, it has an in-built tendency to self-regulate its value. If the supply of cigarettes increases, making them worth less, the holders of the currency have a tendency to smoke them. This reduces supply, and restores their value; all in accordance with the general law of supply and demand.