An Intrepid Window Screen

Our downstairs neighbor replaced some cracked glass in the hallway window, but since it starts getting dark around 4 here in Yankee Land and he has a day job, working on it meant having a giant screen-less hole when all the interior lights were on. I was sure we were going to have a plague of moths, but the next morning I discovered that a temporary window screen had neatly installed herself from corner to corner.
You might need to click on the picture to get a clearer picture.