Millisecond Forums

I am trying to design a simple change detection task where a flash say what quadrant participants need to remember items from and then random colored boxes (with no repetition) are flashed in that quadrant of the screen and then return (sometimes the same colored boxes, sometimes different).  I am having a hard time trying to define where the positions of the boxes are. So far I have this which creates a list with the random colored boxes and then adds them into the memory and test trials, but I cannot seem to define the locations of the list items which is important as I need to say for instance that the first two items in the list show up in locations X1 and X2, while the next items show up in a different quadrant.