Was it still on paper. Man that is such a recipe for disaster.

So my neighbor got one of those little floor cleaning robots last year, the fancy kind that's supposed to map your whole house. Thing got lost in the living room for two hours because my kid left a backpack on the floor. Reminds me of what @anna_craig said about perfect conditions, because it totally failed at the first sign of normal clutter. They had to rescue it from behind the couch, just spinning in circles.