
Artist Stewart Kenneth Moore is best known for his surreal canvases, etchings and comic strips depicting everyone from James Joyce and Vaclav Havel to Macbeth caught in a nightmare of the everyday. But ever since he was a boy, Moore has been fascinated with pi, the ratio between the circumference and the diameter of a circle. It is a mathematical constant and an infinite number, but we generally round it to 3.14 — hence Pi Day on March 14. (The date also happens to be Albert Einstein’s birthday.)

Squaring the circle. Moore assigned pigments to numbers from 0 to 9 and used them paint pi digits. Images credit: S.K. Moore
“I always wanted to paint math,” he said from his home in Prague today, on Pi Day 2016. “In school, I was scared and bored by it. I believed there must be a better way to teach mathematics. I decided to use colors to make it accessible.” Moore assigned pigments to the individual numbers and has painted pi to 2,500 decimal places. “I thought that maybe some pattern or harmony would emerge, just like Seurat’s pointillist paintings,” he said. “When you look up close, there are just dots of paint, but further out an order emerges in your mind and you see colors that aren’t really there.”
But the results have disappointed him. “I felt like I was like painting static on the TV set,” he said. “I realized the problem was with the approach. A color, just like a number, is just a value.” He is now thinking about blending pi in the formula he uses to mix his pigments. “Maybe I have to go deeper.”
Humans have known about pi since they started using wheels 4,000 years ago. Ancient Babylonians could celebrate an entire “Pi Month” since they rounded pi down to 3 (as did the Old Testament).
In 300 B.C., Euclid opened a path for calculating pi by looking at the circle as a polygon with infinitely many sides. Archimedes applied Euclid’s theorems to arrive at pi a few decades later. He also paid for pi with his life. When Roman soldiers occupying his hometown, Syracuse, walked over his math drawings in the sand, he told them to get lost. He never recovered from that mistake. His apocryphal last words? “Do not disturb my circles.”
The inventors of calculus, Isaac Newton and Gottfried Leibniz, used pi to close the gap between algebra and geometry in the 1690s. They used infinite-series techniques to calculate pi to 15 digits.
Twentieth-century mathematicians like India’s Srinivasa Ramanujan used number theory and special mathematical tools called elliptic integrals to find new ways to compute pi even further.
We now know pi to 12 trillion digits, but the job can’t be finished. Although pi’s defined as the ratio between the circumference and the diameter of a circle, it’s also an irrational number that, maddeningly, cannot be expressed as a fraction and runs into infinity. “These things have deep connections with other areas of mathematics,” the late GE mathematician Andrew Barnes told GE Reports. “They take us to the forefront of the greatest unsolved problems.”
Moore keeps thinking about deep connections between math and art. “Math is the language of the universe that we apes have somehow figured out,” he said. “There are numbers everywhere — in seashells, the branchings of rivers and trees, in the spiral pattern of sunflower seeds. I look at the night sky about which we know so much and still so little and I’m baffled.”