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Sander Illusion
The Sander illusion or Sander's parallelogram is an optical illusion described by the German psychologist Friedrich Sander (1889–1971) in 1926. However, it had been published earlier by Matthew Luckiesh in his 1922 book Visual Illusions: Their Causes, Characteristics, and Applications''. The diagonal line bisecting the larger, left-hand parallelogram In Euclidean geometry, a parallelogram is a simple polygon, simple (non-list of self-intersecting polygons, self-intersecting) quadrilateral with two pairs of Parallel (geometry), parallel sides. The opposite or facing sides of a parallelogram a ... appears to be considerably longer than the diagonal line bisecting the smaller, right-hand parallelogram, but it is the same length. One possible reason for this illusion is that the diagonal lines around the blue lines give a perception of depth, and when the blue lines are included in that depth, they are perceived as different lengths. References Optical illusions { ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Illusion
In visual perception, an optical illusion (also called a visual illusion) is an illusion caused by the visual system and characterized by a visual perception, percept that arguably appears to differ from reality. Illusions come in a wide variety; their categorization is difficult because the underlying cause is often not clear but a classification proposed by Richard Gregory is useful as an orientation. According to that, there are three main classes: physical, physiological, and cognitive illusions, and in each class there are four kinds: Ambiguities, distortions, paradoxes, and fictions. A classical example for a physical distortion would be the apparent bending of a stick half immersed in water; an example for a physiological paradox is the motion aftereffect (where, despite movement, position remains unchanged). An example for a physiological fiction is an afterimage. Three typical cognitive distortions are the Ponzo illusion, Ponzo, Poggendorff illusion, Poggendorff, and M� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Matthew Luckiesh
Matthew Luckiesh DSc, DE, (September 14, 1883 Maquoketa, Iowa – November 2, 1967 Shaker Heights, Ohio) was a physicist and, as the Director of General Electric's Lighting Research Laboratory at its Nela Park National Lamps Works facility in East Cleveland, Ohio, he pursued research on light and vision. In his day, he was known as the "Father of the Science of Seeing." Luckiesh developed several theories on color and its physiological effect on people. He was also interested in determining the conditions under which optimal visibility was achieved, and in examining the relationship between light and seeing, in order to design better types of lamps. During World War I he studied camouflage, and later invented artificial sunlight and germicidal lamps. Luckiesh produced eleven U.S. patents, 28 books and about 860 scientific and technical articles, published between 1911 and 1960. Asked how to say his name, he told ''The Literary Digest'' "My name is pronounced as if it were spelled ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Line (geometry)
In geometry, a straight line, usually abbreviated line, is an infinitely long object with no width, depth, or curvature, an idealization of such physical objects as a straightedge, a taut string, or a ray (optics), ray of light. Lines are space (mathematics), spaces of dimension one, which may be Embedding, embedded in spaces of dimension two, three, or higher. The word ''line'' may also refer, in everyday life, to a line segment, which is a part of a line delimited by two Point (geometry), points (its ''endpoints''). Euclid's Elements, Euclid's ''Elements'' defines a straight line as a "breadthless length" that "lies evenly with respect to the points on itself", and introduced several postulates as basic unprovable properties on which the rest of geometry was established. ''Euclidean line'' and ''Euclidean geometry'' are terms introduced to avoid confusion with generalizations introduced since the end of the 19th century, such as Non-Euclidean geometry, non-Euclidean, Project ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parallelogram
In Euclidean geometry, a parallelogram is a simple polygon, simple (non-list of self-intersecting polygons, self-intersecting) quadrilateral with two pairs of Parallel (geometry), parallel sides. The opposite or facing sides of a parallelogram are of equal length and the opposite angles of a parallelogram are of equal measure. The congruence (geometry), congruence of opposite sides and opposite angles is a direct consequence of the Euclidean parallel postulate and neither condition can be proven without appealing to the Euclidean parallel postulate or one of its equivalent formulations. By comparison, a quadrilateral with at least one pair of parallel sides is a trapezoid in American English or a trapezium in British English. The three-dimensional counterpart of a parallelogram is a parallelepiped. The word "parallelogram" comes from the Greek παραλληλό-γραμμον, ''parallēló-grammon'', which means "a shape of parallel lines". Special cases *Rectangle – A par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
