I don&#x27;t think &quot;simple and use a single set of rules&quot; describes the control code for any shipping (action) game.  At least none I&#x27;ve worked on. They&#x27;re all complex piles of special cases and hacks in an effort to make the movement &#x27;feel&#x27; right (which works, but is disheartening at first, until you start to expect it).