Mobility method: conversion into a dual schematic
Every circuit has a "dual"
To obtain the dual circuit, a point is placed in each loop, including the exterior loop (here number 8). These loops then become nodes when moving to the dual circuit.
The elements shared between two independent loops are to be connected between the two corresponding nodes in the dual circuit, and since the change in analogy implies a change in the nature of the elements ; a capacitor becomes a self , a resistor becomes a resistor , etc ...