A friend recently had to cover her windows to hide from someone camped out in front of her home. Blocking her windows gave her privacy, but blocked the light and her view - both important for people self-isolating or in quarantine. Last year, Sandy and I had problems with birds hitting our windows. They would see the reflection of trees in the glass, and try to fly to them. Closing the curtains didn't help, as the outer surface of the glass would still show reflections of distant trees. A lot of stores in our town have covered their windows with advertisements. The window coverings are printed onto sheets of self-adhesive white vinyl, with millions of tiny holes punched into them. The coverings stick on the outside of the glass.We bought some blank pieces of this perforated vinyl from a local sign shop, and stuck it on our windows. Here's a picture of us partway through the job, looking from the outside. It's not hard to put on, just awkward to do it without leaving wrinkles. From the outside, it looks like the window is covered with a white curtain. The green bit is just some painter's tape we used to keep it aligned while we were sticking it up. Here's the appearance from the inside. The inner (sticky) side of the perforated vinyl is black, and is nearly invisible from more than a metre's distance. There is no apparent reduction in light or view (although if we were to measure it, there'd be a 50% reduction, as we used vinyl stock with a 1:1 perforation ratio).