An apparatus for determining wheel assembly alignment comprises a contact assembly, a light source, and a light beam receiving assembly. The dowels of the male jaw fit into holes in the female jaw upon a diagonal line on the mating surface. By providing a shaft on which the lugs may ride, the wires are configured transversely to conventional approaches, enabling a greater number of wires to be connected over a given length and a wider variety of relative orientation of wires. A pressure switch may be disposed in fluid communication with the first fluid path and the second fluid path such that the first fluid path and the second fluid path pass through the pressure switch. This category of rules provides more degrees of freedom in actual application so that the rule-based OPC tool can intelligently select the proper valid rule that minimizes the OPC complexity or meets other objectives. A determination of whether or not the wafer is defective is made in relation to a spatially related group of filtered failed semiconductor chips on the wafer, where the spatially related group corresponds to a localized failure on the wafer and is used to calculate a defect index value.