applications.collages.collageAlgebra:
attributes sR,sG,sB, tR,tG,tB;
{
  xmax = const(26.556),
  ymax = const(99.585),
  
  background = { filledPolygon((-25,-2),(#xmax + 1,-2),(#xmax + 1,#ymax + 2),(-25,#ymax + 2)) },
  
  stem = { filledPolygon((-.6,0), (-.51,16.015), (.51,16.015), (.6,0))<sR,sG,sB; sR=.5,sG=.3,sB=.1> },
  tip = { filledPolygon((-10,0), (0,50), (10,0))<tR,tG,tB; tR=1,tG=.7,tB=0> },
  FERN1 = #tip,
  FERN2 = #tip,
  FERN3 = #tip,
  FERN4 = #tip,
  FERN5 = #tip,
  FERN6 = #tip,
  FERN7 = #tip,
  
  t1 = matrix(.85, .04, -.04, .85) . translate(0,16),
  t2 = matrix(.2, -.26, .23, .22) . translate(0,16),
  t3 = matrix(-.15, .28, .26, .24) . translate(0, 4.4),
  
  fern = < t1, t2, t3, #stem >,
  
  col = colourOperation(tR|1/20:1, tG|1/20:.7, tB|1/20:0),
  col2 = colourOperation(sR|1/10:1, sG|1/10:.5, sB|1/10:.2,
                         tR|1/12:.4, tG|1/7:1,  tB|1/10:.9)
    
  }
