Son 2 often asks me to make swords, pirate ships, hats etc out of cardboard boxes, bits of string, dust etc. The argument that I don't know how to do it is normally met with a "just do it" - followed by tears.
The other day he asked for a submarine to be made from a random box, although I've been watching The Deep (BBC drama) about a submarine I still couldn't recall what a submarine looked like. Look at my effort - does it look anything like a submarine (I though they might have aerials on them that's what the pipe cleaners are)? Son 2 was satisfied for about 2 mins.