 Notice how all the inputs are on the same clocking zone.If parallel data were to be driven at the inputs A, B, C and D, and then driven no more for at least the remaining 15 serial transmission phases, the output X would present the values of D, C, B and A –in that order, at phases three, seven, eleven and fifteen.If a new clocking region were to be added at the output, it could be clocked to latch a value corresponding to any of the inputs by correctly selecting an appropriate state-locking period.