My favorite repeated sibling argument recently*:
Lily, after a Time Out is concluded: “I’m sorry Bewwen… I forgive you.”
Beren: “No, I forgive you.”
Lily: “No, I forgive you!!”
Beren: “No, I forgive you!!!”
(usually ends with a parent forcibly separating them before they’ve hurt each other).
*OK so they’ve already mostly grown out of this one. I’m way behind in the blogging but am going to try to write things more often without trying to get them perfect