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