Four
Imagine contorting yourself in such a way that your mouth now has your legs inside it. You've bent your body in all the wrong ways to achieve this. In fact, if you look at yourself, you look like a square now... You're just a person with four sides.
し
よん, よ
None
Now that you have four sides, you look like a four-sided animal: the sheep (し). Look at yourself in the mirror and see an adorable four-sided sheep looking back at you. Imagine yourself with perfectly square wool. (You can only see four sides because mirrors aren't 3D. So you're a flat, cartoonish sheep.)