The stroboscopic effect is a visual phenomenon caused by aliasing that occurs when continuous motion is represented by a series of short or instantaneous samples. It occurs when the view of a moving object is represented by a series of short samples as distinct from a continuous view, and the moving object is in rotational or other cyclic motion at a rate close to the sampling rate. It also accounts for the "wagon-wheel effect", so called because in video or motion pictures, spoked wheels on horse-drawn wagons sometimes appear to be turning backwards.
(Wikipedia.org)
An illusion of apparent motion or absence of motion that arises when an object or picture is viewed not continuously but during separate time intervals that succeed one another in a periodic manner. An example is the projection of a picture on a screen through a shutter consisting of a rotating disk with slits that alternately passes and shuts off the projecting light. Another example is the illumination of a dark room by periodic flashes of light.
Stroboscopic effects are a result of persistence of vision—that is, the retention in the viewer’s consciousness of a perceived visual image for a short time after the picture or object producing the image disappears. If the time between successive intervals when the picture or object is viewed is shorter than the visual-persistence time, then the images resulting from the discrete acts of viewing are fused into a single image, and the viewer thinks he continuously sees the picture or object.
(Thefreedictionary.com)
Examples of such effect can be found in YouTube.com, an example of which is shown here (taken with a Nokia N95 cellphone)
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