I saw this in a coworker's window earlier this week. This is the view from the hallway:
Since we have engineers from all over the world working here (and because I was just glancing at this out of the corner of my eye), I thought maybe this was a reference to Eton.
But then I went to the office next door to that one and saw:
And now it made sense. When I go outside and look up, I can see this:
Notice how the sticky notes are purple? That's a nice touch! This is pretty hard to see actually since it is behind trees and on the third floor of our building, but you get the idea.
Questions, comments, concerns and criticisms always welcome, John