
Computing Partial Differential Equations with Water - Phithagoras
http://pruned.blogspot.com/2012/01/gardens-as-crypto-water-computers.html
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fernly
In Sir Terry Pratchett's novel _Making Money_ there is a hydraulic analog
computer used to model the economy of Ankh-Morpork[1]. Sounds very much as if
Pratchett might have heard of this Russian one. However according to that
article, the Glooper was in fact modeled after another hydraulic analog
computer, the MONIAC[2].

[1]
[http://wiki.lspace.org/mediawiki/Glooper](http://wiki.lspace.org/mediawiki/Glooper)

[2]
[https://en.wikipedia.org/wiki/MONIAC](https://en.wikipedia.org/wiki/MONIAC)

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andreareina
Not only was the Glooper used to _model_ the economy, in typical Discworld
fashion it came to actually _mirror_ the economy, such that manipulating the
Glooper would cause the same changes in the economy!

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jws
More model than computer, but from 1939 to 1972 there was a water driven model
of the Mississippi River basin used to solve the flood models. It covered 200
acres (a little less than 1 square kilometer) and was useful until computers
replaced it.

[https://en.m.wikipedia.org/wiki/Mississippi_River_Basin_Mode...](https://en.m.wikipedia.org/wiki/Mississippi_River_Basin_Model)

It is unmaintained but is now a park and can be visited.

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fredley
The University of Cambridge has a Phillips machine that works, if you're lucky
it's even possible to get a demonstration. Here's a video of a demo given in
2010:

[https://sms.cam.ac.uk/media/1094078](https://sms.cam.ac.uk/media/1094078)

One interesting thing is that by attaching markers to the floats, and turning
spools of paper on motors, it's possible for the machine to draw graphs as it
operates.

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jgamman
you can see the moniac running if you happen to be in wellington on the
first(?) friday of the month. there's a refurbished one in the foyer of the
reserve bank (invented by a NZer - while employed in another country of
course).

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regularfry
I might be misremembering, but I'm pretty sure the one in the Science Museum
in London runs, too.

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Aardwolf
Only partially off topic: I like the picture "Etienne Dupérac's bird's-eye
plan view of the gardens at Villa d'Este, Tivoli" in the article, and (other
than the fact that it can be seen as a giant water computer) specifically
those multiple maze gardens in there.

The fact that there are multiple maze gardens in there makes me think that
maybe this was not as a cool attraction, but with the actual purpose of
someone being able to walk all the way to the center of it, sit there with a
book or so and have some actual peace and quiet time without too much
disturbance of others?

That's quite different from todays always connected world :)

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motohagiography
A more in depth version of this article that covers more examples:
[http://hplusmagazine.com/2013/05/10/gardens-as-crypto-
water-...](http://hplusmagazine.com/2013/05/10/gardens-as-crypto-water-
computers/)

