Skeleton code for CMYK Fractal experiments (see https://twitter.com/search?q=%23CMYKfractal) ; many modifications and tweaks have been made to shapes / layouts angles along the way, this is just the starting point.

CMYKfractal_basis.pyde

import time

# could MD5 code for unique id, but...
# lets assume we want to save every run.
v = hex(int(time.time())).upper().replace('0X', 'v')
filename = 'circle_%s' % v

def setup():
    size(1680, 800, P2D)
    blendMode(SUBTRACT)
    rectMode(CENTER) # switch between ellipse and rect easier this way
    randomSeed(int(time.time()))
    noLoop()
 
def draw():
  background(255)
  paint(width / 2, height / 2, .5*height, level=int(random(4)))

  if frameCount == 1:  # Save once.
      saveFrame(filename + '.png')


def paint(x, y, radius, level=0):
    noStroke()
    # Set up colors:
    a = map(radius, height, 0, 30, 255)  # alpha
    # RGB + alpha
    colors = map(lambda c: color(*c), [(255, 0, 0, a), (0, 255, 0, a), (0, 0, 255, a)])
    # color based on level; karate-style
    fill(colors[level % len(colors)])
    
    ellipse(x, y, radius, radius)
    
    # Need to stop drawing when we get down to be about the size of a pixel.
    if 2 < radius:
        # ok to recurse!
        nr = radius / 2
        paint(x + nr, y, nr, level + 1)
        paint(x - nr, y, nr, level + 1)