an external input unit configured to input a signal of {HEAD ~ contents} including an image from said {TAIL ~ second wearable display}, said second wearable display being of a second user, 
an external input unit configured to input a signal of { HEAD ~ contents } including an image from said { TAIL ~ second wearable display } , said second wearable display being of a second user ,
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH