This is a model of a sculpture by Karel Vreeburg. The mathematical physicist John Baez paid some attention to the sculture and the European Mathematical Society has used it on a cover for a scientific journal. The torus is split by a triple twisted mobius band (3 times 180 degrees). The resulting object is a trefoil knot. N.J. Wildberger talks about Torus knots in his lecture AlgTop26: Covering spaces(Starting from minute 37) If you are curious about what topology is: See the total beginners course in Algebraic Topology.