The Lego machine is based on the theoretical device set out by Turing in his paper.
Turing described the hypothetical machine as being able to move backwards or forwards over a strip of infinite tape, which is divided into cells. The machine could read, write or erase symbols inside each cell.
The machine would be controlled by a series of rules that tell it whether to move the tape, how to manipulate a cell's contents and which rule to jump to next.
In the Lego Turing Machine each cell on the building-block tape, seen above, is made of a black switch, which can be switched on to represent a symbol or turned off to represent a blank cell.
Photo: Centrum Wiskunde & Informatica