What is periodic motion? Give its examples.

(N/A) Periodic motion is defined as the motion of a body that repeats itself along a certain path at regular,definite intervals of time.
Examples:
$(1)$ An insect climbs up a ramp and falls down; it returns to the initial point and repeats the process identically. If we plot a graph of its height above the ground versus time,it resembles figure $(a)$.
$(2)$ If a child climbs up a step,comes down,and repeats the process,its height above the ground versus time graph resembles figure $(b)$.
$(3)$ When playing a game of bouncing a ball on the ground between your palm and the ground,its height versus time graph resembles figure $(c)$.