Letters Written in Grass

I saw this in the grass alongside a gas station in Liverpool, New York:


That's UNL as in "unleaded," I guess, but I'm not totally sure how it was supposed to be used in the signage at the station.

It lay upon the grass, showing grass blades through the letters, and I knew that if I lifted it up, I'd see more letters printed by the sun:


And sure enough, there they were.