Don't Tread on me

On the way home from school Jacob and I were having one of our deep conversations.
Jacob had to bring something oval today and he brought an oval shape from a puzzle.
He told me what other kids had brought. Then as we were driving, we were looking around to see what else was oval. I named, "eggs, watermelons, footballs."
He corrected me, "Footballs aren't oval!"
Mom "What shape are they then?"
Jacob, "They are football-shaped!"
Mom, "A football shape is an oval shape!"
Jacob now screaming, "NOOOOO! Mrs. Micheel (Jacob's teacher) said footballs are NOT ovals!"
Mom, "Well, if Mrs. Micheel said that then I'm not sending you to school because she's wrong!"
A few minutes later as we are naming more of "Jacob approved" oval shapes. Jacob says, "There are oval houses in Tanzania."
This causes mom to look away from the road, right at Jacob. "Tanzania? Tanzania!" Jacob says matter of factly, "Yep, oval houses in Tanzania."
What in the heck??? Where did that come from? I'm guessing Mrs. Micheel... or or or...