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The Jump & Smile is a type of fairground ride in which the chair cars are arranged on a number of radial arms around a central axis. As the central axis rotates, the arms are lifted into the air at pseudo-random intervals giving an erratic jumping motion. There is another version called Techno Jump, which had a specific pattern in which the cars would go up one at a time, and then shake a little when up. Then the ride would suddenly drop up and down in order, creating the illusion of moving waves and the sound of pistons going "ch-ch-ch-ch-ch-ch". Also this ride would freeze in midair, making riders think it was over before starting to do the same jumping motion backwards.
Source of the article : Wikipedia