applications.collages.collageAlgebra:
{
  branch = { filledPolygon((-3,0),(3,0),(3,40),(-3,40))<0,0,0> },
  
  f1 = scale(.6, .7) . rotate(35) . translate(0, 13),
  f2 = scale(.65, .7) . rotate(-30) . translate(0, 13),
  f3 = scale(.6, .65) . rotate(-3) . translate(0, 23),
  f4 = scale(.75, .7) . rotate(2) . translate(0, 0),
  F = <f1, f2, f3, f4  >,
  
  g1 = scale(.6, .7) . rotate(30) . translate(0, 13),
  g2 = scale(.6, .7) . rotate(-35) . translate(0, 13),
  g3 = scale(.6, .6) . rotate(3) . translate(0, 21),
  g4 = scale(.75, .7) . rotate(-2) . translate(0, 0),
  G = < g1, g2, g3, g4 >,
  
  side = colourOperation(r|1/10:1/2, g|1/10:3/4),
  top  = colourOperation(r|1/5:3/4 , g|1/4:1  ),
  bot  = colourOperation(r|1/5:1/4 , g|1/5:1/6)
  
}
