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• So if I wanted to make one I would use what i see here? Nothing is hidden inside it? (I know how the ball dispenser works.) I just want to know it will work the same if﻿ I just use what is visible here.

• The lower﻿ paths from the four leftmost holes (at 1,2,4,8) is a simple return path. The other holes (top, right) are used for clearing the register and﻿ as part of the 2's complement operation. So, yes, there are things hidden inside for the latter two operations. Look at the original Digi-Comp II patent for a full explanation: US Patent 3390471.

• When﻿ I search for the patent I get something called GODFREY. It does not really show what is in the mechanism. Do you know a good place to look for patents or what to search for.

• Godfrey is the name of the author of the invention/patent. READ the patent; view the pages. They do show illustrations of what's on the bottom side.﻿

• I﻿ went to digi-compii website and it says that Evil Mad Science would be selling kits in 2012. Is this true? I would really like to order one. Is there an estimated release date?

• Sorry, behind schedule. :( Still﻿ working on it.

• Imagine using this in a maths﻿ exam

• Actually, neither of us are programmers. Why is it that people make stupid assumptions and snide comments? Oh yeah, they're﻿ just rude commenters on youtube, with *nothing to contribute to society*. (eye-roll)

• i want one!﻿

• Thank you for doing this. I can't say that I understand it, but I﻿ get the idea.

• It's not about speed, it's a proof of concept, of how a digital computer calculates.

The interpretations are merely decimal/binary conversions for humble humans easier reading. Binary speaking the machine really does perform the﻿ multiplication

11 * 1101 = 100111 no conversion needed.

Largest possible result in one go binary 1111111 ~ 127, though larger when using the overflow control.

• So you have to do the addition in your head to set the equation and﻿ then again to interpret the result. Seems like it would have been quicker to just do the original sum in your head. What is the largest number this device can multiply?