Strip the computer part
How to make 'screen' behave.
Forget about the computer's underlying constructions.
programming languages are symbol based time waste.
In order to do something with programming, you need to know underlying api which talks to hardware resource. There are three hardware resource. display, space, time. Its monitor, cpu, and storage. but lets stick to fundamentals.
When trying to build using programming language brain effort gets consumed for obselete APIs. Reducing the underlying system, it boils down to display, space, time.
Display is the fixed size in hardware, so scratch it.
Whats left? space and time. Keep a dot on space, move your position forward. What happens? the point of dot is backward. When it comes to time, there are two point of observation. One within the space and another focusing on space.
Everypoint can be a point of reference to another point.
A point has a reference point, what if the reference point of the moving point also moves?