Thus, a desired time varying pattern of energization of {HEAD ~ the conductors} to accomplish a control function, e.g. the control of a central heating system to provide {TAIL ~ different heat outputs} at different times of the day, can be set up at will simply by adjusting the various switches  
Thus , a desired time varying pattern of energization of { HEAD ~ the conductors } to accomplish a control function , e.g. the control of a central heating system to provide { TAIL ~ different heat outputs } at different times of the day , can be set up at will simply by adjusting the various switches
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 OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH