Varying the length of three sides of a hyperbolic right angled hexagon - a Geogebra App.
Random walk in the Poincare disk.
Dissecting Hypercubes with Pascal's Triangle | Infinite Series
Coxeter explains the mathematics behind Escher hyperbolic paintings.
Klein quartic I, by Jos Leys
Klein quartic II also by Jos Leys
Dodecahedral tesselation of the hypersphere by Jos Leys