Difference Engine #3 was inspired by Charles Babbage's Difference Engine #1, which is commonly regarded as the first computer in the world. A Bi-Directional Browsing Unit (BBU) with a movable camera captures an image of the visitor standing before it at the press of a button. The image is then assigned an identity number and displayed on the monitor in a 3-D representation of the Media Museum ZKM in Karlsruhe. The image of the visitor then embarks on a brief journey through the ZKM. After that, it moves to a Purgatorial Site, where it cycles continuously with other images of previous visitors. Eventually it is archived permanently on the Internet. These images can be viewed on a large projection screen and can be recalled on the Internet at any time via the identity number. Online visitors can choose one of five avatars (virtual representatives) provided and steer themselves through the ZKM. The BBU enables online visitors to see into the exhibition space of the O.K from the perspective of the real visitors via the live video feed from the camera. A dedicated chat-line allows online visitors to communicate with the visitors in real space.
Difference Engine #3 was developed for the ZKM.