Images: Patenting sandwiches, pet toys

Critics of the U.S. patent system say that it too often rewards ideas that are obvious and which rightly belong in the public domain. Supporters, on the other hand, argue that inventors' ideas must be protected.

At right is a diagram illustrating one idea that has won such protection: "Method of excercising a cat." This concept--using a handheld device to manipulate a laser beam that can "amuse and exercise" a feline--is protected by U.S. Patent No. 5,443,036.

Photo by U.S. Patent and Trademark Office