In an alternative embodiment, apparatus 38 may have {TAIL ~ three discrete operating states}: “HIGH,” “LOW,” and {HEAD ~ “OFF}” which may be selected by “flipping” an appropriate switch 
In an alternative embodiment , apparatus 38 may have { TAIL ~ three discrete operating states } : “ HIGH , ” “ LOW , ” and { HEAD ~ “ OFF } ” which may be selected by “ flipping ” an appropriate switch
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH