They weren't being creative, they were being naughty. The paint was up in a place they weren't supposed to be(they made stairs out of something to get to it), and from what it sounds like, got paint they weren't supposed to have all over downstairs. They knew they were in trouble. This is a good technique for teaching the boys. Ask them a lot of questions, ask them if they know what they did was wrong, and tell them how they were going to be punished and why. He wasn't laughing on purpose, I doubt anyone could keep from laughing at those two like that. He's obviously a good father.