Smarts

Sierra and I were driving home from our adventure today and I can't remember what started the conversation, but I said, "How did you get so smart?" As best as I can remember and decipher my notes here is the conversation.

me: How did you get so smart?
Sierra: Screws and a tool to make me smart.
me: A tool?
Sierra: Yes, a tool that makes me smart. It hits me on a screw which makes me smart.
me: It hits you on a screw?
Sierra: yes.
me: What hits you on a screw?
Sierra: I have an assistant in my brain.