A person goes to bed at sharp 10.00 pm every day. Is it an example of periodic motion?
Here, the person is going to bed sharp at 10:00.
But what about his motion, if we take his bed as the reference he might take different paths every day. Someday he might follow.
(1) Bed - Bathroom - Bus stop - Office - Bus stop - Bed
(2) Bed - Bathroom - Cab - Office - Restaurant - Bed
So every day the path might be different, even if the path is same the velocity might be different (at the same time on different days)
Example: He might go to his office every day but the speed of a bike and a car and a bus will be different.
Clearly, the motion is not periodic.