But that pattern wouldn't be allowed on a stop sign, it would have to almost entirely obstruct it to work since we're so used to looking for the shape and even a hint of red, all it took to confuse the AI was a word above and below that covers a very small percent of the area. Stickers on stop signs are ubiquitous in a lot of places, so this is a fairly probable situation, whereas I've never in my life seen a stop sign that was so obstructed that I wouldn't recognize it. I'm sure someone could design a stop sign the machine could recognize and we couldn't but that's not what's on the roads and arguing about that is pointless because the amount of infrastructure you'd have to replace to get there is so massive that it's not relevant.