There are literally thousands of headlight styles and shapes across all vehicles years, makes, and models. Here is a list of "Application Notes" for headlight configurations where the best installation approach may not be obvious.
1. Headlight Not Under Hood (HNUH)
If the top edge of your headlight is not next to your hood, or only partially next to your hood.
2. Flip Up Headlights (FUL)
3. Classic Round Headlights (CR)
4. In Gap Above Headlight (IGAH)
5. Newer Cadillac (NCAD)
6. Inside Headlight Surround (IHS)
7. Headlight with Large Edge (HLE)
8. Mercedes CLK (POTATO)
9. Smart Car (SMART)