Strange Calculation Devices

This is a site about unusual and old-fashioned calculation devices and computers.
The site is currently under construction.

Some examples of strange calculators are:
Marble adder
Marble arithmetic unit built from Lego parts
An adder using water (fluidics)
Robinson's model of Babbage's Difference Engine #2
Water clock by Bernard Gitton (not quite a full calculator but very interesting)
Harry Porter's relay computer
My own homebuilt R 500/7 T relay computer

More information and details about my own relay computer will be provided on this site.
Preliminary: Overall Architecture

Last update: January 16, 2012