A sequential circuit has two inputs, w1 and w2, and an output, z. Its function is to compare the input sequences on the two inputs. If w1 — w2 during any four consecutive clock cycles, the circuit produces z = 1; otherwise, z = 0. For example

w1 : 0110111000110

w2 : 1110101000111

z : 0000100001110

Derive a suitable circuit.