A sequential circuit is to be designed to monitor the status of a chemical experiment. Every 10 s the circuit receives an input pattern between 0001 and 1111. If the input pattern received is 0111, the experiment is assumed to be continuing perfectly; the input patterns 0110 and 1000 are also considered satisfactory. However, if the circuit receives any other binary pattern twice consecutively, the experiment must be stopped. Derive a state diagram of the sequential circuit and a complete logic diagram using JK flip-flops as memory elements.