9. A navigation light on a point in a lake flashes 1 s on and 1 s off. After three flashes, the light stays off for an extra 2 s. a. Let 1 represent "on" and 0 represent off." Sketch a graph with time on the horizontal axis to represent the
flashing of the light. Include three cycles.
b. Explain why this pattern is periodic.
c. What is the period of the pattern?
d. What is the amplitude?

Please help.