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geometric illusion
geometric illusion A geometric illusion is a visual misperception in which a simple geometric feature is seen differently because of the pattern around it.
A geometric illusion is a visual misperception in which a simple geometric feature is seen differently because of the pattern around it. In the Müller-Lyer illusion, for example, the same line can look different in length depending on whether it ends with arrow tails or arrowheads.