Herding Invisible Cats

You might think the subject line is an elaborate metaphor, but you'd be wrong.

You know that logic puzzle where you have to transport a wolf, a sheep, and a bale of hay across the river in a canoe and can only carry one of them at a time? My current logic puzzle involves two very skittish cats, a house with many hiding places, a garage with many hiding places, and a house-to-garage door that doesn't always latch properly. It happened something like this...

About a month ago, I took delivery of two new-to-me cats whose owner had died. Between the disappearance of their owner, the chaos of large numbers of strange people packing up their home, the trauma of being forcibly caught and put into carriers, and the strangeness of their new environment, the cats decided that they were in imminent danger of being devoured alive and promptly hid (see inventory item "house with many hiding places"), only sneaking out in the dead of night to eat, drink, and use the litter box.

They became, in a word, invisible. There were occasional brief sightings at night (did you know that all cats are gray in the dark?) but other than that the only evidence of their presence was what was taken and left. Hold on to that thought.

Due to seasonal house settling, the house-to-garage door currently needs forcible encouragement to latch properly. (See relevant inventory item.) This is done when I leave the house, but not always when I'm at home. Air pressure differentials sometimes leave the door slightly ajar. See also inventory item "garage with many hiding places".

After a while, the gray cat (did I mention there is a gray cat and a black cat? but all cats are gray in the dark?) began venturing timidly into visibility. This was reassuring. The black cat had not yet made an appearance for some time, but was known to have been the more skittish of the two. And the amount of food disappearing and...um...deposits in the litter box seemed consistent with the presence of two cats, though it varied from day to day.

And then, Sunday afternoon, I opened the door to the garage to move the laundry to the dryer and saw a black cat dash for cover. See inventory item "garage with many hiding places". See also "door that doesn't always latch properly." So now I had confirmation that the black cat was located in the garage (and was alive!), but no confirmation of how long it had been there or where it was hiding. I also made an assumption, though a warranted one, that the black cat in question corresponded to the one I had taken delivery of.

Here, then, is the logic puzzle: how does one move the black cat from the garage to the house under the following restrictions:

• Neither cat will appear in the open when human is present
• Gray cat must not leave house
• Black cat must not leave garage by door to street
• Both cats must have regular access to food, water, and litter box
• Neither cat can be relocated by physical interaction
• Presuppose a non-finite number of food and water dishes and litter boxes

Oh, and one bonus given condition is that the gray cat likes to hide under the bed in the master bedroom and can be identified in that location via flashlight.

Here, then, is my strategy for herding invisible cats. (Please note that this story is told for entertainment purposes and is NOT a request for advice, assistance, or catsplaining.)

1. Move one (1) litter box, one (1) water dish, and one (1) food dish into the master bathroom. (A previously unmentioned logistical requirement is that said items may only be located in non-carpeted areas.)
2. Ascertain that the gray cat is under the bed in the master bedroom.
3. Close and latch the master bedroom door. Keep door closed at all times except when human is entering or exiting. The first bullet point ensures that there will be no cat movement in or out of the master bedroom under these conditions.
4. Place one (1) litter box in garage and one (1) litter box in family room. Also one (1) water dish in both locations. Clean and rake litter boxes so that any activity is visible.
5. Place one (1) food dish inside the house visible from the house-to-garage door.
6. Prop house-to-garage door open when going to bed. (Shudder at the anticipated heating bill.)
7. On rising, check and re-clean litter boxes in garage and family room. Verify that water is available in both house and garage but food only in the house. Close and latch house-to-garage door. Double-check proper latching. Go to work.
8. (To be completed) Return from work at ascertain based on litter box status whether the black cat is now located in the garage or the house.
9. If garage, repeat from #5. If house, remove cat equipment from garage and use a combination of heavy object and latch double-checking to prevent regression into garage. Open door to master bedroom. Adjust locations of interior cat equipment.

You may notice that the third bullet point (black cat must not leave garage by door to street) has not been accounted for. On this one, I must trust to previous behavior (obviously the cat is still in the garage despite the coming and going of the car twice a day), presumably driven by the first bullet point (neither cat will appear in the open when human is present).

When I took delivery of the cats, they came with names that didn't feel right to me. Thanks to a suggestion on Twitter, the top name candidates are currently Schrodinger (for the cat that either is or is not in the garage) and Cheshire (for the cat visible only as glowing eyes under the bed).