Instructables user craft-tech writes:

Should you wear a scarf today? Hang this piece of tapestry on a (drafty) window, and the embedded lights will tell you at a glance what the temperatures could feel like. The piece contains 6 lights: 2 red, 2 green, and 2 white. A smart temperature sensing module turns on the appropriate lights without any extra programming. I really think Grandma could get into this :-)