@MightyBigCar oh I really appreciate all your analytical suggestions! I thought it was some sort of internal Electronic Thingie™, but from what? I tend to have either my phone or laptop with me most of the time, and did when I noticed the thingies, but three identical ones? On different days? I'm stumped. They look intentionally crafted, otherwise I too would have thought they were from a fabric mesh. I'm gonna have to chalk it up to witchcraft. Or space aliens.