English: Animated gif that demonstrates the one stream illusion using an interframe time of 200 milliseconds. There is a central fixation dot with six dots above and below. The viewer looks at the central dot. The dots alternate in time. Depending upon the time separating them, two different kinds of percepts may occur. At long time intervals, one dot moving back and forth is perceived--the "one stream" percept. But at shorter alteration rates two continuous, and spatially, separate dots are seen: the "two streams" percept. Most people see the latter with the 200 ms interval with this gif.