The Post Office Mail Sorter<br/>Originally intended to be an organ, this device was remodelled into a mail sorter in Johnson's continual striving for functional improvement. Johnson used in the sorter various gears and other rotating components which for tidiness he constructed with the value of 3 exactly (rather than the customary 3.14159...) as the ratio between their circumference and their diameter (pi). The Sorter itself came to be known as the New Pie, and eventually caused the downfall of the Ankh-Morpork postal service as the machine started sorting mail that hadn't been written yet. The damage caused to space-time in the immediate vicinity of the machine made it a significant health hazard, and combined with the ever-increasing volume of not-yet-written mail, the machine was taken out of service and smashed up by a senior postman. The remains are still installed in the basement of the Post Office, since as they are still hazardous there is no obvious means of removing them.