Complex resistor networks often have symmetries that simplify analysis. Key techniques: (1) Identify equipotential points — if two points are at the same potential by symmetry, the resistor between them carries no current and can be removed. (2) Folding symmetry — if the network is symmetric about the input-output axis, points equidistant from the axis are at equal potential. (3) Star-delta (Y-delta) transformation — convert between configurations to enable series-parallel reduction.

Classic example: resistance of a wire cube between diagonally opposite corners. By symmetry, the 12 resistors (each R) carry currents in only 3 distinct values. Using KCL and symmetry: $R_{eq}$ = 5R/6 (opposite corners of cube).