I've made an afghan a year for about 10 years now, but I'm working on a shawl this year. Made a baby afghan in a pattern that used popcorn stitch and created an effect similar to the border of a fancy cake. I get a magazine called Creative Knitting (which used to be Knitters Digest) and it always has at least two patterns per issue for afghans.
The most complicated one I made for a brother's wedding. IT was 16 squares, 12" each, in different patterns for each square. I made the corners the same (a heart pattern) and the center square was a candelabra, that looked more like a family tree. (Every row of the pattern for that square was different.) I tried to make another a few years later for myself, but couldn't get enthused about the work involved in sewing them together! I like to knit, hate to sew.
I found a book in a batch of patterns my stepmom sent me (which she got from someone else, but thought they were too good to throw away -yay!) that is patterns for doing Amish style quilts made out of crocheted blocks, patterns like Trip Around the World.
I think in the book, they are made separate and sewn together.
I bet it would be possible to do at least some of it with color changes.
A new project for later!