Binary Adder Made of Wood and Marbles

Here’s a wooden binary adder that uses marbles for the bits. Be sure to watch the video demonstration - you only realise how clever the design is when you see it in action, especially as the carry bits cascade through the digits.

There’s plenty more to see on the rest of the site, including Marble Machine 2, an ingenious piece of kinetic art, and photography using a flatbed scanner.