Illuminating hyperbolic geometry

Joint work with Saul Schleimer. In this short video we show how various models of hyperbolic geometry can be obtained from the hemisphere model via stereographic and orthogonal projection. 2D figure credits: 4:09 Cannon, Floyd, Kenyon, Parry. 0:49, 1:20, 1:31, 2:12, Roice Nelson. We thank Gazi University, Ankara, Turkey, for its hospitality during filming. (2,3,7) triangle tiling: Geodesic saddle ({3,7} radius 3, subdivided 4): Pseudosphere: (2,3,5) triangle tiling (stereographic projection): Thanks to M.Y. Zhang for writing CC subtitles for this video.