Hello all! I've just finished putting together a small deck box where my cat's litter box fits perfectly. I've cut an opening for him in the front, padded the sides of the opening, and placed a box in front for a step. He is happily going in and out with no hesitation. He is 22 and blind, but highly adaptable, doing so well ; ))) Now, I want to create a simple flap to cover the opening, to aid in odor control. I'm trying to figure out what to use. I'm not handy enough to create a rigid swinging flap. I'm figuring cloth; but it can't be too light or too heavy. Maybe a piece of canvas? I do have sheet vinyl, maybe a piece of that, it's just thick marine-style clear vinyl. I want him to still go in and out without being bothered by the flap. Has anyone done this before? What do folks recommend?