Spirograph With Four Pens Drawing 140 Curves at Once | 4K

Four pens draw one spirograph of 140 curves, and it fills the whole screen. A spirograph is a small wheel rolling inside a ring, with a pen in a hole in the wheel. The curve it draws is called a hypotrochoid. The tooth counts of the ring and the wheel decide how many lobes the curve has. The position of the pen hole decides how round or how pointed each lobe is. Here one ring and one wheel make 140 curves at once. Each curve has its own pen hole, spread from inside the wheel's edge to outside it, and its own colour, so the rainbow is the row of pen holes. The gear pair changes through the piece: 5 to 3, 7 to 2, 8 to 3, 12 to 5 and 11 to 4, which give 5, 7, 8, 12 and 11 lobes. Each pair lasts 24 seconds, and the figure eases into the next one over the last 6 seconds. Twice every two minutes the pen holes glide from inside the wheel to outside it and back, and the whole figure turns once every two minutes. The picture is scaled so the outer curves run past the corners of the frame. Four pens sit evenly round the row of 140 curves and move round it once every 16 bars, which is 28.5 seconds at this tempo. Each pen draws the curve at its tip, keeps the curves behind it, and erases the last ones. The bright dot at each tip is the pen. Nothing here is filmed or drawn by hand. Every frame is worked out as arithmetic: about 50 million points a frame at 4K, added up into light. Which gear pair do you like best: 5 lobes, 7, 8, 12 or 11? Chapters: 00:00 Intro, pens waiting 00:14 The beat starts 01:09 Fuller sound 01:40 Loudest stretch 02:36 Winding down #spirograph #hypotrochoid #generativeart #phasemusic