It's time for a brief lesson in quantum mechanics! Exciting I know. See, there's the fabric of reality as you know it, but the thing about fabric is it has to hang on something, or rest on something, or be folded haphazardly on something. That something is what I call the in-between space. Every universe has to bump up against other stuff out there, and that stuff isn't always another universe. So what is it, exactly? Hell if I know.