We love 3 1/2" strips! They show off more of the fabric than 2 1/2" and they are quicker to sew. This "invisible" 4 Patch has been a favorite of ours for years. We have called it Madame Butterfly when we made it of 28 Asian strips. In the Fryer Patch pattern version I called it What Four, because you can't tell that is is made up of 4x4 patch blocks.
This variation uses 14 "dark" strips and 14 Background strips. The background can be cut from a single fabric or different fabrics. The fabrics can be high contrast or low contrast/blending. With borders it finishes 63"x 77".