Minimal architecture

A vaulted cellar full of brass machinery. Coloured liquid runs through glass pipes into four great glass tanks, each holding a small city of towers and domes in blue, amber, green or red. Below them a console of gauges and levers feeds a ticker tape printed with pictures of the city, steam rises from a boiler beside a flywheel, and a clerk in a waistcoat turns a red valve wheel beside a map of the pipes pinned to the wall.

Hubert’s Glooper, in the cellar of the Royal Bank, was built to show where the city’s money went, and turned out to decide it. Any model of a city takes that risk, and a game takes it on purpose. This machine is agreed on paper before a single pipe is laid. Hubert built his first and asked questions afterwards, which in Ankh-Morpork is the traditional order.