Just like ring tones, door knockers can be a statement of intent.  From northern to southern Spain, there are a vast variety of door knockers: some of them works of art, some of them more of utilitarian objects.  Here are the more beautifully crafted ones.
| A welcoming one. It says: "Eat me" | 
| A suggestive one. It says: "I want you...." | 
| My favourite one - It says: "I embrace you" |