Moving Objects - Not Collapse Just Touch And Stop

Let's say we have a matrics of coordinates:

(0,0) (0,10) (0,20)

(10,0) (10,10) (10,20)

(20,0) (20,10) (20,20)

And we have a class that draws a rectangle of 10 pixel height and 10 pixel width at 0,0 coordinates.

And we want to move with the arrows the rectangle but not to go off the frame.

The question is:

How can I do that if I draw another rectangle, it knows where is the other object and they not collapse. And so on, they move, but not collapse, just touch and stop.