Jeroen van den Bosand and Davy Landman did just that, and they made a that details how they created a out of Lego bricks. The pair of researchers made the machine not only as a tribute to the great mathematician and computer scientist, but also to demonstrate how simple computers can be.

The pair used a Lego Mindstorms NXT kit to get their version of the algorithm machine running. The build uses a light sensor to determine the value of each of the Lego Turning Machine's 32 switches--if a switch is on, the sensor sees a black brick; otherwise, it sees a white space.

The sensor reads a command from the switches, which are moved along by gears, and an orange lever can change the position of each switch to issue a command. Software-wise, the pair used the to make the thing work.

It's easier to watch than to explain, so :

Aside from the fact that you can't provide an infinite supply of Lego bricks (unlike the real Turning Machine's tape), the end result is quite impressive. And like the actual Turing Machine, the Lego rendition can manipulate symbols and explain how a present-day CPU in a computer works. In this case, it can add two and two together.