My scrap quilts look something like deplaylady's picture above. but I use much smaller "crumbs". I start with a very small, really pretty, bright one; add another about the same size; and continue adding tiny strips around like a log cabin. The pieces I add are whatever shape I pick up. It won't be square until I get near the size I want. The only thing that needs to be straight is the line I am sewing. I've made several like this, and found that smaller blocks look better than 12 in. blocks. On the big blocks the strips get long and not as scrappy looking; but you could make these strips out of pieces also. The sashing adds a nice touch.
Happy scrapping!