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