"The problem’s dimension influences the dimension of this shape: With two variables it takes the form of a flat polygon; in three dimensions it is a Platonic so

"The problem’s dimension influences the dimension of this shape: With two variables it takes the form of a flat polygon; in three dimensions it is a Platonic solid, and so on." It certainly needn't be a _Platonic_ solid! The author must have meant to write merely "solid" or "polyhedron" or some such thing