A cycle is defined by repeatedly developing a start signal at {HEAD ~ the beginning} of {TAIL ~ each cycle} 
A cycle is defined by repeatedly developing a start signal at { HEAD ~ the beginning } of { TAIL ~ each cycle }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL