I think the funniest "Leap" illustration I ever saw was in the book The Calculating Cat Returns by Eric Gurney. It draws a cat trying his first munch of catnip, getting increasingly ecstatic and operating clumsy ballet leaps around the room to finally smack his head when he leaps under the kitchen table. I had the book when I was a kid, and when I first saw it I laughed for a half hour. Every time I looked at it after I got the giggles. I saw it at the library recently and it can still make me smile and snort. It's not the head getting smacked that's so funny, but the exaggerated look of discovery, and joy and, well a cat that was high as a kite.