Rhombic tiling, permutation plot, subset gamegraph, permutahedron, hyperplane arrangement, structure diagram, three-dimensional heap, Cayley diagram, braid graph, and L-tromino tiling.

I highly recommend watching this video of Professor Michael Starbird (University of Texas) presenting his insights into the philosophy of teaching at the Mathematical Association of America PREP Workshop called “Using Inquiry Based Learning in Second-Year Calculus and Courses for Prospective Teachers”, which took place at UC Santa Barbara, June 2012.