applications.collages.collageAlgebra:
{
  ntColour = const(.8),
  xmax = const(26.556),
  ymax = const(99.585),
  
  stem = { filledPolygon((-.3,0), (-.255,16.015), (.255,16.015), (.3,0)) },
  sample-outline = { closedCurve((0,0),
                                 (23,28) left (-7,-21) right (3,9),
                                 (#xmax,#ymax) left (-10,-22.5) right (-18,-5),
                                 (-22,43) left (3,9),
                                 (0,10),
                                 (0,0)) },
  sample-filled = { filledCurve((0,0),
                                 (23,28) left (-7,-21) right (3,9),
                                 (#xmax,#ymax) left (-10,-22.5) right (-18,-5),
                                 (-22,43) left (3,9),
                                 (0,10),
                                 (0,0))[#ntColour,#ntColour,#ntColour] },
  sample = #sample-filled + #sample-outline,
  FERN = #sample,
  FERN1 = #sample,
  FERN2 = #sample,
  FERN3 = #sample,
  FERN4 = #sample,
  FERN5 = #sample,
  FERN6 = #sample,
  FERN7 = #sample,
  
  rect = { polygon((-4,0),(4,0),(4,16),(-4,16)) },

  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 = < #stem, t1, t2, t3 >
    
  }
