Brain Twister

So, Venice and I have been having circular conversations a lot lately. I can't even remember what they are, but they always go something like this:
Venice: Mom, what kind of car is that?
Diana: It's a convertible. It has a roof that comes off.
Venice: I knew that.
Diana: You rode in one once.
Venice: In what?
Diana: One of those kinds of cars.
Venice: What kind of car?
Diana: A convertible.
Venice: The kind where the roof comes off?
And so on and so on and so on.

This example shows, of course, my responses being even keeled and polite. I often lose it and get frustrated and try to explain that she just asked the same thing again and how I just answered that and how we're talking about the same thing over again, yadda yadda yadda. At one of these times, when I was trying to explain how we just had this conversation, she got frustrated back and grumbled, "Can we just forget about it." and before I could get on her case about giving me attitude she added, "Because you're just twisting up my brain and it's confusing me." It was all Chris and I could do to keep from laughing.