31. In hyperbolic geometry rectangles do not exist. 32. In hyperbolic geometry ( where Wallis's Postulate is false ) similar triangles are congruent. 33. Negating the Axiom of Euclid yields hyperbolic geometry , while eliminating it outright yields absolute geometry. 34. Euclidean, elliptical and hyperbolic geometry . 35. It is one of a series of four woodcuts by Escher depicting ideas from hyperbolic geometry . 36. He finally reached a point where he believed that his results demonstrated the impossibility of hyperbolic geometry . 37. In 1913 and 1914 he bridged the gap between hyperbolic geometry and special relativity with expository work. 38. In hyperbolic geometry the sum of angles in a hyperbolic triangle must be less than 180 degrees. 39. Hyperbolic geometry is frequently referred to as " Lobachevskian geometry " or " Bolyai Lobachevskian geometry ".40. In the latter case one obtains hyperbolic geometry and elliptic geometry, the traditional non-Euclidean geometries.
