I have been performing an experiment where I place progressively smaller shoeboxes upon my futon and wait to see how long it takes for a cat to curl into it. Unfortunately, it appears I have reached the end of the experiment: This box sat on the futon for about a day before Mencken decided to test it out. Mencken tried his best, turning around and around and around in the box, but finally couldn't manage anything but doing the catloaf while hanging his head over the front.
So now you know the limits of what a 14 pound cat can fit in: A sneaker box is it. I have a smaller box that sandals came in, but somehow doubt it will get anything more than a sniff from the feline brigade.
-- Badtux the Cat-owned Penguin