Here is another example. Notice how the first slider doesn't create an events. When the second slider is updated, it polls the first (looks at its value).

Change the first slider to affect how the second one moves.

Or with a checkbox (buttons are mainly good at generating events):

speed:

Or, even this.... (which isn't that much different)

go:

The thing to notice here is that the "loop" runs even if the slider isn't moving! In this case, it's pretty wasteful. But it gets at the main idea of animation loop programming: the loop keeps going, and each iteration it checks to see if something happened. In contrast, standard event-driven programming only does things when something happens.