A new specie

摘要

Small tribes have often used unique forms of money. Until recently, west Africa's Ashanti had perhaps the oddest. Eschewing the convenience of metal discs, stones or shells, they used metal painstakingly moulded into the shape of small chairs, representing the tribal chief's throne. But the latest cult currency-Bitcoin-is stranger still. Invented in 2009, this computerised money exists only as strings of digital code.