Speaking of pet doors, I get mail occasionally from pet lovers who castigate me, some gently and some not-so, for allowing Ludwig to be an indoor/outdoor cat. It is wrong, they say, to subject a cat to the perils outside the home. I have my opinions about this argument in the real world, but I will keep them to myself, because arguing pets is akin to arguing religion. However, I do have the perfect defense in Ludwig’s case: Ludwig is a cartoon cat; nothing can happen to him that I don’t cause to happen. A perfect defense still will not deflect the inevitable rejoinder, “You should set an example with your work.” I surely don’t want to go there.