We had a car in the 80's (I think)---it was a GM Hornet, which had front seat covers that were white with black dots all over. The dots were the size of pencil erasers and kind of closely spaced, in even rows. Over time all the black dots, every little one of them, deteriorated out, just like you described, so we ended up with white seat covers with evenly spaced holes. That was so weird. I always wondered if it was from a dye created in a third world country or if it was because the black retained heat/sun so much more than white in a hot closed car.