Not as easy as it sounds! I backed pages from Death on the Nile with fusable interfacing, then sewed it right sides together with a fabric scrap. I left one long side completely unstitched so I could sort of awkwardly turned the whole thing inside out. The seams are a lot more durable than you’d think and only tore when I jabbed a chopstick in too hard, to try and neaten the corners up. First prototypes, and I have to say the combination of fabric, interfacing and paper results in a very sturdy material.