Ventilation decorations

A few days ago someone posted a photo of the ventilation in the subway asking if anyone else had noticed that a few of the holes were not circular but cut into other shapes. The person received tons of photos from people who had seen hearts, pacman, squares, diamonds etc etc. Today as I was going home I noticed that the ventilation next to me had three crowns 👑 👑 👑 cut out. How funny. Must be a sign from our pride and joy! 

Has anyone else of you seen this?