The present invention provides a contact surface between the blade of a surgical retractor and an underlying tissue that directly reduces the injury of the tissue caused by the application of pressure during the retraction process. One embodiment of a network device having router functionality includes a processor, memory in communication with the processor, and program instructions. The passage as a first portion extending in a first direction from the inlet and a second portion extending from the first portion to the outlet in a second direction, opposite to the first direction. A portion of the polysilicon layer is then removed to form a plurality of dummy patterns. Each one of a second level of power indicators is associated with a different one of the devices.