Imagine this in the dark... How do you explain if someone is bouncing a glowing basketball and it can appear the ball is moving away (to the left or right) in one situation and just bouncing it up and down in another situation. I think this has to do with field of reference but I'm honestly very confused. This is basically the question "Discuss how the observer’s movement, the basketball player’s movement, and the observer’s position relative to the basketball player affect the observer’s perception of the ball’s motion"