Eric is challenged to come up with a way to place four trees so that each one is exactly the same distance from the other three. It's not magic ... it's mathematical! The pedagogical side: This segment illustrates another strategy for solving problems: making a model. By using miniature trees to try to solve the problem, it becomes obvious that a two-dimensional solution is impossible. Eric figures out that the problem requires a three-dimensional solution: the tetrahedron. This segment is about geometry and the tetrahedron - a three-dimensional object.