What are some examples of symbolism in The Kite Runner?

I think that there are many examples of symbolism in the Kite Runner.

1- The kite represents the freedom and bonding of Amir and Hassan, both at the beginning and end of the book.

2- The slingshot represents devotion. In the beginning, Hassan used it to stand up to Assef in the alley, and then at the end, Hassan's son Sohrab used it to protect Amir against Assef after returning to Afghanistan.

3- Assef's brass knuckles represent fear. Everytime that Assef would come up to Hassan or Amir, he would have his hands up and be ready to fight them. In the end, this is really in effect. This happens when Assef beats up Amir when he comes back to Afghanistan.

4- The Ford car given to Amir by Baba symbolizes their changing relationship.