Every other panel has {HEAD ~ a passageway} near its top region and the alternate panels, relative to the every other panels, have passageways located at {TAIL ~ their bottommost region} 
Every other panel has { HEAD ~ a passageway } near its top region and the alternate panels , relative to the every other panels , have passageways located at { TAIL ~ their bottommost region }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL