Jim Denevan loves many things--surfing, cooking, movement, spirals, and the land. He creates large scale drawings, freehand with no measuring aids, all within the canvas of the land itself. He loves to create in the sand--artwork that is then photographed and gone. He uses a rake or a piece of driftwood and walks for hours, sometimes up to 30 miles to create a complex geometric drawing.
He has also used an ice canvas for his creations. In 2010, he created spiral of circles along a Fibonacci curve. The circles were as small as 18" and up to several miles in diameter. The location was Lake Baikal in Siberia.
This video is a wonderful look into his process: