This is a redstone port of the Digicomp II (https://www.youtube.com/watch?v=_tZdE-3nR3w)
Accoring to wikipedia it was "a toy computer invented by John Thomas Godfrey, that used marbles rolling down a ramp to perform basic calculations."

I have replaced the rolling balls with 1 tick redstone pulses, and the switches with T flip-flops. It operates exactly like the original.
It can do basic arithmetic, aswell as some intresting calculations, e.g. calcuating the tragectory of a ballistic missile
(page 60 of manual: http://cdn2.evilmadscience.com/KitInstrux/DCII-manual.pdf )

(I was not able to make a video explaining this, as footage recorded on my laptop is very jittery)

An example of a calculation: what is 5*6? (see screenshots for clarity)
1. enter 5 into multiplier register (yellow area) in binary (101) by breaking and placing the light blue wool
2. enter 6 into the memory register (blue) in binary (110) by flicking the levers
3. make shure all the wool in the oragne area is in the left position and all wool in the green area is in the right position, and that the multiply switch is set to yes (near the start button)
4. click the button and the calculation starts
5. After the calculation finishes, the result should be *spoilers* 11110 (30 in decimal)