"In terms of size, a d-ary tree of n leaves has (n − 1)/(d − 1) internal nodes for a total of (nd − 1)/(d − 1) nodes in the tree"
"Because the area of a triangle can be written as base · height/2, and because for each of the previous ratios the triangles involved share the same base, the previ- ous expressions simplify to ratios of heights"
"To avoid degeneracies, the projection is made to the plane where the projected areas are the greatest."