Think of MEB as a set of abstract parts with default implementations. If you want to change the whole vehicle, you only have to change certain parts. Make these

Think of MEB as a set of abstract parts with default implementations. If you want to change the whole vehicle, you only have to change certain parts. Make these pieces bigger, these pieces smaller, etc. A true skateboard would be a static implementation of the frame and propulsion system, with defined interfaces for the "top hat" (industry term for the body of the vehicle).