The MONIAC or Phillips machine is a hydromechanical analog computer built to teach basic economical principles using colored water flowing in transparent pipes. The machine was built in 1951 after electrical-engineer-turned-economist William Phillips and his economist colleague Walter Newlyn realized that flows were used as a metaphor to teach economics, but have never been made physical. Phillips is also known for his eponymous curves. Several MONIACs were built, and a working one is permanently displayed at the Economics Department of Cambridge University. Sources: Bissell (2007) The Moniac: A Hydromechanical Analog Computer of the 1950s. The museum of the Reserve Bank of New Zealand also has a working MONIAC and a Youtube video explaining it. Image from fulltable.com. Morgan & Boumans (1998) The Secrets Hidden by Two-Dimensionality: Modelling the Economy as a Hydraulic System. The original article by the creator of the machine: Philips (1950) Mechanical Models in Economic Dynamics.

Scientists keep using solid models to help them better understand complex 3D data (here, an astrophysical simulation): They say this provides even more insight into what’s going on. “The ability to hold and inspect the 3-D printed models provides a new perspective on the WWIR’s geometry and an improved sense of the scale of the different structures,” they say. In particular, they say the model allows them to appreciate just how large the shockwave is compared to the stars and the distance between them. Sources: Clive Thompson (2015) Astronomers print 3D models of colliding solar winds. Madura et al (2015) 3D printing meets computational astrophysics: deciphering the structure of η Carinae’s inner colliding winds.