Out of curiosity, I looked up string art and was amazed to learn about who invented it: Mary Boole! The Mary Boole.
Who is she, you ask? Boole was a mathematician married to another mathematician. She spoke at conferences and attended meetings for Charlotte Mason's PNEU schools. While her name never appeared in any of the six volumes, M. E. Boole wrote many articles on science and mathematics for The Parents' Review.
In case you are new to Charlotte Mason's ideas, I have two more reference points. Mary Boole's maiden name was Everest — as in Mt. Everest. Her uncle was Sir George Everest, the English surveyor who worked in Java and India, home to the tallest mountain in the world. Her husband was also named George — George Boole -- a genius in mathematical logic and probability. He developed what we call Boolean algebra, which is the logic that drives the device you're using to read this.
Do you know what is amazing about this? I made a curve out of a series of straight lines. This arc is called a parabola, something you probably hated in Algebra II.
P.S. I made the file in a *ahem* spreadsheet!