an external output unit configured to output a signal of {HEAD ~ contents} including {TAIL ~ an image} to said second wearable display, and 
an external output unit configured to output a signal of { HEAD ~ contents } including { TAIL ~ an image } to said second wearable display , and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH