These ideas extend to finding the areas of the results of overlaying more than two input maps simultaneously. As with two maps, the output half-edges are derived from input edge endpoints and intersections of edges. What is new is that the location of each half-edge must be determined in every input map. In this case, the advantage of OVERPROP compared to actually finding a sequence of more and more complicated intermediate maps would be even greater. There would also be no artifacts resulting from the order in which the several input maps were processed, since they would all be used together.