Great idea for a modular knit blanket. One simple shape makes a great quilt. Sidewalk Quilt by Pippa, an original design. Pattern available on her website and a similar version for sale in her Etsy shop.
I know this is a quilt and NOT crochet but it is crochet inspiration. I think a granny square afghan made like this would be really cool and actually pretty easy to do. crochet,Crochet of 13 boards),patchwo