a first wearable display and a second wearable display of {HEAD ~ the plurality} of {TAIL ~ wearable displays}, the first wearable display having: 
of
a first wearable display and a second wearable display of { HEAD ~ the plurality } of { TAIL ~ wearable displays } , the first wearable display having :
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH