That’s Elvis the dog, not Elvis the person. Elvis belongs to Tim Pennings from Hope College and likes to play fetch on the beach. When he went to catch a tennis ball, he’d run along the beach for a while and then swim. So his owner checked, and it turned out that he was using the nearly optimal path for reaching the tennis ball.
The video above is from CNN and a friend just sent it to me (thanks Ginny!). In doing a search I discovered that although I hadn’t heard it before, it’s been around for a while: Ivars Peterson wrote about it in Math Trek five years ago. Still, a story that features both calculus AND an Elvis? I couldn’t resist.