I was just reading the last chapter of Using Drupal which treats Drupal Commerce and there it says that every product has to have a unique ID but these products can be grouped by product displays. Like when you have a T-Shirt in 10 colors and 4 sizes that's 40 products that can be organized by a single product display. But I have a physical product which has several regions and every region can have one of several thousand designs (different colors, patterns,...). This means billions or even trillions of combinations and I can hardly create a product for every one of those. How do I solve this problem?