Examining FIG 6 in more detail, {HEAD ~ this figure} is a simplified line representation of the front of {TAIL ~ a users} head 200 as seen from the top 
Examining FIG 6 in more detail , { HEAD ~ this figure } is a simplified line representation of the front of { TAIL ~ a users } head 200 as seen from the top
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH