The base of {TAIL ~ electrodes} of transistors Q1 and Q2 are fed {HEAD ~ a controller} 14 via lines 15, 13, respectively as shown 
The base of { TAIL ~ electrodes } of transistors Q1 and Q2 are fed { HEAD ~ a controller } 14 via lines 15 , 13 , respectively as shown
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH