Ants
This sign isn’t really reproaching the person who left the doughnuts at the tech office, but letting them know that if they wish to get have ants in the office, this would be the right way to go. Obviously, this passive-aggressive message is meant to say, in nicer words, “don’t leave doughnuts in the office!”
Since, well, why would anyone want to have ants around the office? This is a good message, because it isn’t just saying, “don’t leave doughnuts,” but mentioning what will happen if they do.