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