Billy McConnell discusses equations relating the angles and face areas of tetrahedra. Heilbronn triangle constants . Helicopter and triceratops , covered with strips of triangles by the Stripe program. Icosamonohedra , icosahedra made from congruent but not necessarily equilateral triangles. The isoperimetric problem for pinwheel tilings .
Isosceles pairs .
Stan Wagon asks which triangles can be dissected into two isosceles triangles. Jordan sorting . Richard Kenyon's Gallery of tilings by squares and equilateral triangles of varying sizes. A map of all triangles and the search for the ideal scalene triangle , Robert Simms. Monge's theorem and Desargues' theorem, identified .