The Flicker by Tony Conrad from 1966 is a classic in the genre of structural film. The work is based on two essential sources of inspiration. Firstly, during his study of mathematics, Conrad dealt with experimental psychology and in particular with treatment methods involving flicker effects. Secondly, as a member of the Theater of Eternal Music since the early 1960s, he was one of the first representatives of minimal music and worked on a nomenclature for rational frequency ratios.
The Flicker is a black film interspersed at varying intervals with transparent images, which causes the generation of stroboscope like light effects in a frequency of four to twenty-four light flashes per second. Because the human eye cannot adequately process the extremely rapid sequence of light flashes, effects are produced on the retinas of the viewers that are in each case distinct. Viewers describe effects that range from colors to patterns and photograph like illusions. The composition on the soundtrack is similarly minimal and is reminiscent of the noise made by a 16 mm projector. The primary difference between The Flicker and Dwinell Grant’s Color Sequence or Peter Kubelka’s Arnulf Rainer is the extremely rapid alternation: the film is preceded by a warning that it can elicit epileptic seizures in people prone to having them. Even if there are no documented examples of this having ever occurred, with its duration of thirty minutes The Flicker is nevertheless a borderline cinematographic experience.
 See http://www.geocities.com/hstencil/tonyconradintro.html (accessed February 3, 2009).