One embodiment of the invention sets forth a technique for avoiding collisions between agents traversing different lanes of a multi-lane path in a crowd simulation. In some embodiments, initial input to the system is accomplished by taking a digital photograph of an electrical device surface in order to capture text or other marks such as barcodes from which power usage of the device can be determined. When WRITE, CHRDY and RA1 all become \u201cH\u201d, an output signal from the NAND circuit becomes \u201cH\u201d, and a write current flows through the write word line. The head may include components that can be adjusted to alter the position of the proximate end of the handle on the head and to alter the head weight balance andor orientation.