Interesting machine, the mother of all the computers we know today:
LEGO Turing Machine from ecalpemos on Vimeo.
"This is a short documentary about the LEGO Turing Machine built by Jeroen van den Bos and Davy Landman at Centrum Wiskunde & Informatica (CWI), Amsterdam (Netherlands). They built it for CWI's exposition "Turings Erfenis" in honor of Alan Turings one hundredth birthday this year.
Alan Turing was a brilliant mathematician who helped define the theoretical model of the computer as we know it today. He was a visionary, one of the few people of his time who recognized the role the computer would play for humanity.
The Turing Machine (1936) is an adequate model of a computer. It can do anything the computers of today or tomorrow can do."
This LEGO Turing machine uses a tape based on a classic interpretation of computer memory: switches. Additionally, it uses a light sensor to determine the value of a switch: if the switch is on, the sensor will see the black colour of the switch's surface. But if it is turned off, the sensor will see the white colour of the LEGO beam, making it possible to distinguish between the states. Finally, a rotating beam mounted above the tape can flip the switch in both directions.
Alan Turing's original model has an infinite tape, but LEGO had a slight problem supplying infinite bricks. So we chose to fix our tape size to 32 positions.