Dreamachine

Dreamachine
From Wikipedia
The Dreamachine (or Dream Machine) is a stroboscopic flicker device that produces visual stimuli. Artist Brion Gysin and scientist Ian Sommerville created the dreamachine after reading William Grey Walter's book, The Living Brain.
In its original form, a dreamachine is made from a cylinder with slits cut in the sides. The cylinder is placed on a record turntable and rotated at 78 RPM or 45 RPM. A light bulb is suspended in the center of the cylinder and the rotation speed allows the light to come out from the holes at a constant frequency, situated between 8 and 13 pulses per second. This frequency range corresponds to alpha waves, electrical oscillations normally present in the human brain while relaxing.
A dreamachine is "viewed" with the eyes closed: the pulsating light stimulates the optical nerve and alters the brain's electrical oscillations. The "viewer" experiences increasingly bright, complex patterns of color behind their closed eyelids. The patterns become shapes and symbols, swirling around, until the "viewer" feels surrounded by colors. It is claimed that viewing a dreamachine allows one to enter a hypnagogic state.[citation needed] This experience may sometimes be quite intense, but to escape from it, one needs only to open one's eyes.
Link to a full screen Dreammachine: http://www.netliberty.net/dreamachine.html#

A dreamachine may be dangerous for people with photosensitive epilepsy or other nervous disorders. It is thought that one out of 4,000 adults will experience a seizure while viewing the device; about twice as many children will have a similar ill effect.
Brion Gysin and the dream machine are the subject of a feature length documentary film by Nik Sheehan called FLicKeR. It is co-produced by the National Film Board of Canada, and features Genesis P-Orridge, Iggy Pop, Marianne Faithfull, John Giorno, DJ Spooky and Kenneth Anger, and is currently in the final stages of post-production.