this is a wonderful project, that I have been following for a while.
I thought at some point in the past I've seen a circles logo, which was basically just a blue circle, but couldn't find it any more.
In any case, I liked that idea very much, because it reminded me of a japanese Ensō (https://en.wikipedia.org/wiki/Ens%C5%8D).
I don't fully understand the symbol in the Logo that you just posted (Is it the letters making up the word "circles"?). In any case, here a poor manifestation of what I thought I had seen before.