Cool Calculator made of Wood

Wood Calculator

This calculator is made of wood and works with marbles. It can do a number of types of sums by dropping marbles down from above. When the marbles drop down the rockers move in to position and then the marbles fall in to the correct place which gives the answer to the sum. I some how dont think that you will be allowed to take this in to an exam though. Still cool though and well worth checking out.

Via: Woodgears