A frictional engagement element that disconnects power between an engine and a drive wheel in a vehicle, and a control unit that controls a transmission ratio of a continuously variable transmission and the frictional engagement element, are provided. In one embodiment, a method of tracing a raster image includes generating a planar map having at least one region, at least one edge, and at least one vertex, identifying topology of the at least one region, and applying the planar map to the raster image to create a traced image. The method further includes computing a sensitivity of the failing slack to each of a plurality of variables and comparing each sensitivity to a respective sensitivity threshold. Applications include fibers, yarns, nonwovens, carpets, other fibrous materials, films, coating and composites. In one implementation, conductive rails of the 3-D monolithic memory device are formed by etching an oxide layer such as silicon dioxide using the patterned amorphous carbon layer as a hard mask.