A penguin rolling down a hill.
Explanation: This joke uses repetition to create a funny mental image. The setup, “What’s black and white, black and white, and black and white?” prompts the listener to guess something involving alternating black and white patterns. The punchline, “A penguin rolling down a hill,” humorously explains the repeated colors as a penguin’s natural black-and-white appearance flipping over and over as it rolls. The unexpected visual of a penguin in such a comical situation makes the joke amusing.