If you have a cat, you’ve probably wondered what escapades your feline friend gets into when you’re not around. Jürgen Perthold, a German-American engineer, was similarly curious about where his cat, Mr. Lee, went when he disappeared from his South Carolina home, so Perthold designed a special camera for him to wear. Weighing less than 3 ounces, the camera is engineered to capture continuous photographs for two days straight and fits around the cat’s neck. It took several attempts, but eventually Mr. Lee returned with the camera intact and photographic evidence of his days-long adventure. Perthold published the...