Look, what's that on the railway tracks, David? A rock? A man?Oh, it’s a tree trunk.Gosh! A train is coming soon! It’s going to hit it! Let’s move it away.There's no time for that. We must stop the train. Let’s wave at it.But we always wave at trains coming by. And the drivers are used to our waving.We must wave something red. Red is for danger.Good idea. Your T-shirt is red. Take it off!Sure.
