Allowing overlaps makes switchbox layouts nice

Advanced technology and missing theory require new research in overlap routing models. The author investigates switchbox routing problems in a Manhattan-like model, generalized to more than two layers allowing an arbitrarily long overlap of two or more wire segments. The author gives techniques to solve any switchbox routing problem restricted by the well-known cut condition in this model using a very small, often minimal number of vias. The number of layers remains constant in any case