DS used to do the same thing, mostly when he started a pre-school at 3. they said they wouldn't have academic stuff which is why I put him there. But I observed one day and they held up a circle and asked DS what shape it was. He said it was a hexagon and then laughed. It was white and he said it was pink. I never cared, just thought he was bored and making a game out of it. He didn't do it forever in school...just for a bit. And whenever I would agree or say "right" he would quickly be like "no, no, that's not what shape it is" and we would play back and forth. I loved all the silliness because it ends too quickly.
