Great idea to do with old t-shirts from sports, rodeo, etc. Since t-shirt fabrics are stretchy, they need to be stabilized prior to cutting out the squares. A lightweight, woven fusible interfacing that has little or no stretch will do the trick.
Skinny Strips Quilt-Stitch an easy-to-sew quilt using a variety of precut strips. Blue prints from the Clermont Farms collection by Minick and Simpson for Moda Fabrics are combined with chalk-white fabric to make a patriotic quilt