One of the strips is then turned end to end without rotation, so that both faces on the upper surface are {HEAD ~ either inner faces} or {TAIL ~ outer faces} 
One of the strips is then turned end to end without rotation , so that both faces on the upper surface are { HEAD ~ either inner faces } or { TAIL ~ outer faces }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL