topical slide(s): creative technology / new media / game development(s)

each node in a 2-d tree implicitly represents a region $R_N$ .
in general, each node N has at most four associated constraints that jointly define the region represented by that node.


     XLB: x >= c1; XUB: x < c2; YLB: y >= c3; XUB: y < c4;