The birth of a True Equilateral Triangle from Isosceles parents is the subject of rejoicing in our country for many furlongs round. After a strict examination conducted by the Sanitary and Social Board, the infant, if certified as Regular, is with solemn ceremonial admitted into the class of Equilaterals.

Flatland: A Romance of Many Dimensions, Part I, Section 3 (p. 21), Little, Brown & Co. 1899