... pi in the sky:
On the afternoon of September 12, 2012, artist ISHKY, with Stamen Design, launched Pi in the Sky, a project that used skywriting to create quarter-mile tall digits at 10,000 feet over the San Francisco Bay Area. It took a team of five synchronized skywriters equipped with dot-matrix technology to create the first one-thousand numbers of the infinite order of pi (3.14159, etc.). The airplanes made a 100-mile loop around the Bay Area, which created a temporary piece that was 150 miles long.