Equiangular polygon Equiangular polygon In Euclidean geometry, an equiangular polygon is a polygon whose vertex angles are equal. If the lengths of the sides are also equal (that is, if it is also equilateral) then it is a regular polygon. Isogonal polygons are equiangular polygons which alternate two edge lengths. The only equiangular triangle is the equilateral triangle. Rectangles, including the square, are the only equiangular quadrilaterals (four-sided figures). For a convex equiangular "n"-gon each internal angle is 180(1-2/n)°; this is the "equiangular polygon theorem". Viviani's theorem holds for equiangular polygons: A rectangle (equiangular quadrilateral) with integer side lengths may be tiled
Geometry pipelines to the vertices of polygons, or other geometric objects used as modelling primitives, as part of the first stage in a classical geometry-based graphic image rendering pipeline. Geometric computations may also be applied to transform polygon or repair surface normals, and then to perform the lighting and shading computations used in their subsequent rendering. Hardware implementations of the geometry pipeline were introduced in the early Evans & Sutherland Picture System, but perhaps received broader recognition when later applied in the broad range of graphics systems products introduced by Silicon Graphics (SGI). Initially the SGI geometry hardware performed simple model space