The sequencer 12 is controlled by sequencer control apparatus 14, which contains {HEAD ~ the components} required to direct two electric motors contained in the sequencer 12 to perform {TAIL ~ the vertical and horizontal rotations} described above 
The sequencer 12 is controlled by sequencer control apparatus 14 , which contains { HEAD ~ the components } required to direct two electric motors contained in the sequencer 12 to perform { TAIL ~ the vertical and horizontal rotations } described above
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH