I have forgotten who, but someone wrote a book on Shadow Quilts. The idea is to use larger and smaller versions of the same block. On some of hers, the larger ones were less intense, thus, shadows. Some of hers had several different sizes of blocks.
This is my own variation on the theme. My grand niece wanted a quilt in fall colors. I gathered a lot of fabrics and used about 1/3 of them. I know I'll emjoy the rest as well.
BTW, I finished the quilt today, except for de-linting.
One thing I know is that she appreciates a quilt. I have made her 2 previously which she enthused over.