I like the idea of making a simple 9 patch using colors from the busy sidewalks fabrics. Besides the dark green, I'd get lighter green, red, pink, and small size holiday prints to make the 9 patch. Then I'd use the sidewalk fabric for the alternating setting squares between the 9patch squares. If you cut your 9 patch squares at 4 1/2", it would make a 12" block (after all seams are sewn) then you could cut your sidewalks fabric at 12 1/2".