applications.collages.collageAlgebra:
{
  ntColour = const(.8),

  tip = const(8.66),

  line = { polyline((0,0),(10,0)) },
  sample-outline = { polygon((0,0),(10,0),(5, #tip)) },
  sample-arrow = { filledPolygon((10,0),(8.2,.7),(8.2,-.7)) },
  sample-filled = { filledPolygon((0,0),(10,0),(5, #tip))[#ntColour,#ntColour,#ntColour] },
  sample = #sample-filled + #sample-outline + #sample-arrow,
  S = #sample,
  
  f0 = scale(.5,-.5) . rotate(60),
  f1 = scale(.5) . translate(2.5,#tip / 2),
  f2 = scale(.5,-.5) . rotate(-60) . translate(7.5,#tip / 2),
  F = < f0, f1, f2 >
  
}
