I've been having conversations with Giotto di Bondone (c. 1267 - 1337, born in Florence, Italy) since I was twelve years old and my class studied the Renaissance. The conversation became obsessive when in 1987 I created a cycle of paintings recreating the paintings of the Arena Chapel on seven shaped canvases, the largest of which is 18 by 24 feet. You can see them here.

There are three stories about Giotto. One is that as a child as he drew a sheep on a rock, Cimabue saw this and was impressed and invited him to become his apprentice.Another is that one day while Cimabue was out Giotto painted a fly on Cimabue's self portrait. It was so realistic Cimabue tried to whisk it away several times. Many years later, the fly became a symbol of the artist and was inserted frequently into Dutch still life paintings. But it is the third story that has occupied me recently.

Vasari, the chronicler of "Lives of the Artists", relates that when the Pope sent a messenger to Giotto, asking him to send a drawing to demonstrate his skill, Giotto drew a red circle so perfect that it seemed as though it was drawn using a pair of compasses and instructed the messenger to send it to the Pope. The messenger departed ill pleased, believing that he had been made a fool of. The messenger brought other artists' drawings back to the Pope in addition to Giotto's. When the messenger related how he had made the circle without moving his arm and without the aid of compasses the Pope and his courtiers were amazed at how Giotto's skill greatly surpassed all of his contemporaries.[6] [Wikiwand]

This winter when I started to paint circles, of course I thought of Giotto, but never more so than when I began to draw them on a large canvas.

To do this I dropped into a meditative state. If I thought too much about what I was doing my mind would interfere with my hand. I used silver graphite so that the line would catch the light. I wanted a field that was made from a line.

I thought, had "the string theory" proven to be true, it might look like this. Here is a close up: