Equilateral polygon with 60° internal angles. An equilateral quadrilateral is called a rhombus, an isotoxal polygon described by an angle α. It includes the square as a special case. A convex equilateral pentagon can be described by two angles α and β, which together determine the other angles. Concave equilateral pentagons exist, as do concave equilateral polygons with any larger number of sides. An equilateral polygon which is cyclic (its vertices are on a circle) is a regular polygon (a polygon that is both equilateral and equiangular). A tangential polygon (one that has an incircle tangent to all its sides) is equilateral
Triangle and Robert Triangle and Robert Triangle and Robert is a webcomic by Patrick Shaughnessy that ran from August 1999 to September 2007. It is about the adventures of two polygons, an equilateral triangle named 'Triangle', and a rhombus named 'Robert'. As Patrick Shaughnessy, appearing in the strip as 'the Cartoonist', has explained on many occasions, he can't draw, and he makes up the story as he goes along. All of the characters are simple shapes that he creates using a cheap paint program. More complicated objects are represented by simpler stand-ins (a sheep, for instance, appears as a rectangular placeholder marked "Insert