Design a sequential circuit with two D flip-flops A and B, and one input x_in. When x_in = 1, the circuit goes through the state transitions from 00 to 01,

to 11, to 10,back to 00, and repeats. When x_in = 0, the circuit goes through the same sequence above, but backwards. The value of x_in can change at any point in time. Therefore, the circuit may reversedirection at any point and follow the sequence in the other direction from that point.