This question is a follow up on: Open a pop up window that runs a calculation in loop until it is closed?
How can I open a pop up to show a picture of a triangle that rotates by 2 PI/100 around its center every Pause[1/1000] seconds as long as the space bar is held down? Is this possible in mathematica? (An answer where it constantly rotates regardless of key strokes interests me too.) What I am trying to get at is that I would like to have a honest infinite while loop of regular commands sent to the pop up window that terminates only when the pop up is closed.
EDIT
Maybe I should just stop simplifying and ask the actual case that I am eventually interested in. I want to display two images, one on top of the other and call an external function each loop. If the function gives back 1 one of the images jumps up and down, if the function returns 0, both images are static. How would one go about writing this?

Refresh, which is what comes to my mind when an updating image could be desired. – LLlAMnYP Aug 21 '15 at 10:05