Congruence Classes of Geoboard Triangles
This Demonstration displays all the congruence classes of triangles on an geoboard. For example, on a geoboard, there are 79 congruence classes.
 M. S. Meagher, M. T. Edwards, and S. A. Özgün-Koca, "What's Your Answer? Searching for Triangles," Mathematics Teacher, 109(7), 2016 pp. 500–506. www.jstor.org/stable/10.5951/mathteacher.109.7.0500.
 D. J. Rusin. "A028419: Congruence Classes of Triangles Which Can Be Drawn Using Lattice Points in Grid as Vertices." The Online Encyclopedia of Integer Sequences (N. J. A. Sloane, ed.). (Mar 10, 2016) oeis.org/A028419.