Work on this painting stretched over five months, from November 2015 to April 2016.
I know this because for the first time I got methodical about the cell-phone photos I habitually take at the end of the day. This time I set up a tripod and hit the shutter every time I remembered it, sometimes with a timed delay. In the end I had taken 1,235 photos, enough to put together an entertaining time-lapse instant replay of the process:
Even to me, that seems like a lot of circles.
Here are a few of them close-up:

Photos of the finished painting installed at Blank Space Gallery in NYC: