A very clever joke, deserves an upvote! As a friendly piece of advice, though, the format could use a little bit of work. The order I naturally read this in went like this "Bark bark-> why you can't tell knock knock jokes to dogs-> knock knock". If you had the cat and dog on top, with the cat to the left and the dog to the right, then put the commentary box on the bottom, it would have been much easier to read and understand. Keep up the clever jokes and keep learning, you'll do great!