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