Did you know that every January 29th is "National" Puzzle Day? I put that word in quotes because I highly doubt that an act of Congress made this holiday truly national.
Here's a vintage jigsaw puzzle-shaped sticker from KUOM in Minneapolis, Minnesota.
KUOM is an Alternative/College Rock station operating from the University Of Minnesota. They also carry a variety of specialty music shows including Metal, Ska, Jazz, Hip Hop and Punk as well as news and sports coverage.
Radio experimentation at the university began as early as 1912. In 1922 the first broadcast license in Minnesota was granted to the UoM with the call letters WLB. This long history makes what is now KUOM the 10th oldest station still on the air and the oldest non-commercial radio station in the country.
This is a "Radio K" sticker showing the logo which was used from 1993 until 2007. You can see the current logo at their website.