user
Given a cartoon image and a caption. Caption: The piano's in tune, but the house is a little flat. Question: Generating an explanation of why this image/caption combination is funny. Answer: 
assistant
A play on words: "flat" can mean that an instrument is out of tune, like the piano could be (but isn't). The house is literally "flat", however, i.e.: it has been flattened to the ground.