8. Draw a state machine that takes four bits as input and detects whether the four-bit value is zero or non-zero. 9. Find something in the real world whose behavior can be described with three or four states. (That's an arbitrary requirement to keep the assignment reasonable. Two states is too simple, and five states starts to get too complex.) Draw a finite state machine for your real-world system. Include reasonable labels for the states and label the triggers that cause a change between states.