The top (red) row of rectangles represents 1/1, 2/1, 3/1 etc, the second (green) row 1/2, 2/2, 3/2 etc.
“From” means that that fraction is in the upper-left corner.
Red=1, green=2, yellow=3, blue=4 etc.
And.. what it might look like as a rug. The bigger the better. I mean, would need a huge wall mural or something to start seeing some interesting high numbers with lots going on in each rectangle. I didn’t get even up to a 100×100 square in any of these ones so far.