FIG 4 shows {TAIL ~ a movable mechanism} of {HEAD ~ the heater} with FIG 3 
FIG 4 shows { TAIL ~ a movable mechanism } of { HEAD ~ the heater } with FIG 3
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH