Tiling a Sphere with Special Right Triangles
This Demonstration shows the tiling of a sphere using spherical right triangles with dihedral angles of , and . The triangles can tile in exactly three different ways .
 R. J. MacG. Dawson and B. Doyle, "Tilings of the Sphere with Right Triangles I: The Asymptotically Right Families," The Electronic Journal of Combinatorics, 13, 2006 Research Paper #R48, www.combinatorics.org/ojs/index.php/eljc/article/view/v13i1r48.