The outboard-brain hits paydirt again. Paul Mison comes up with the goods this time – pointing me to the liquid and pipes simulation of the national economy that I was struggling to find:

“Take a pile of Perspex tubes, a few levers and pulleys and the windscreen-wiper pumps from an old wartime bomber. Add a brilliantly ingenious kind, as bucketful of water, and what do you have/? A computer that can model the flow of money around the nation. If the government raises taxes or the public goes on a spending spree, then this bizarre bit of plumbing shows what happens to the country’s savings and investments. At a quick flick of a switch the strange contraption can reveal the wisdom of increasing government spending or the folly of cutting interest rates. This huge machine, knocked up in a barrage by one-time crocodile hunter Bill Phillips, is now on display at the Science Museum in London. But in the 1950s, the computer model that ran on water was streets ahead of its electronic contemporaries. “

» Megabyte: A liquid computer