As a result, the first resistor R1, in series with the second resistor R2, is connected in {TAIL ~ parallel} with {HEAD ~ the fourth resistor} R4 
As a result , the first resistor R1 , in series with the second resistor R2 , is connected in { TAIL ~ parallel } with { HEAD ~ the fourth resistor } R4
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH