The spiral lollipop guild?

On a number of street signs around Montpelier there are stickers, about the size of a hand with fingers extended, on which a spiral is depicted. It's a simple spiral of a solid color, and the color varies from one sticker to another: some green, some blue, I think I saw one red. The spiral is on a white background, and has only one additional feature: at its outer end, there's a little tail, giving it a shape kind of like a lollipop, but with much too small a stick for the candy part. If you look at the image here, rotate it between a quarter and half turn, add a "tail" about a quarter as long as the circle's radius, and color it green, you'll have a good idea of what one of them looks like.

They're stuck (obviously by some third party) onto speed limit and other navigation signs with no apparent rhyme or reason. The only really consistent part is that the tail points down at an angle, though not always the same angle, but never straight down.

Someone went to some effort to produce these things and bring them around town and stick them in a number of places, but I have no idea who, or why. I tried using Google searches to find a picture of the same symbol, with no luck -- but that might not prove much, since there's not a lot about them that lends itself to unique keywords. Google also failed to turn up anyone else posting anywhere about anything like this, but again, the lack of good keywords might be responsible.

Is it some pop culture element of which I am ignorant (and there are surely many of those)? Is it a symbol of some belief or organization which wants to display itself but doesn't feel any need to make those of us outside the mystery able to find out the answer? Is it some kind of performance art, and if so, is my reaction what the artist intended?

I'm going to try to remember to take a picture of one of these so I can post it here. Maybe someone will know what they represent.