Finite state machines: counter
	q1	q0	x	q1+	q0+
	0	0	0	0	0
	0	0	1	0	1
	0	1	0	0	1
	0	1	1	1	0
	1	0	0	1	0
	1	0	1	1	1
	1	1	0	1	1
	1	1	1	0	0
	1b. New state
		input 0: no change
		input 1: increment