Eyecode (Golan Levin, 2007) is an interactive installation whose display is wholly constructed from its own history of being viewed. By means of a hidden camera, the system records and replays brief video clips of its viewers' eyes. Each clip is articulated by the duration between two of the viewer's blinks. The unnerving result is a typographic tapestry of recursive observation.
More information: flong.com/projects/eyecode/