hiding places for cats

I don't have a cat, but my sister does. They've lost her a couple of times in the linen closet. She'll get in behind a stack of towels and they won't see her when they shut the door.

Her favorite hiding place is under the treadmill, though. They cannot figure out how she squeezes under it because it's low to the ground. She isn't a small cat. Yet, sometimes they will go in the room and they'll see two eyes poking out from underneath it.