2d packing for rectangular shapes

i am trying to fill in a shape with random sized diamond like shaped geometries in 2d. even squares would be a start, i tried to use the circular packing scripts to create squares with the circles' center points etc, but it does not work exactly as i want. 

think of rhombohedral diamond shaped rectangles packing, and their sizes change according to an attractor. here is my problem, i am not able to put different sizes of shapes. for example there's a 6x6 square, i can fill in with 1x1 rectangles, 2x2 or 3x3 ones.. that's ok. but i want to fill with 1x1,2x2 and 3x3 ones. and my script should decide that if it is too far from my attractor point or curve, it should put a bigger shape. if it is near my attractor curve, it should fill in with more and more smaller ones. and my problem gets a little bit confusing when i aim to use diamond like parallel edged shapes, not squares :) 

any help or ideas will be appreciated. thank you.