applications.collages.collageAlgebra:
{
  ntColour = const(.8),
  reduce = scale(.8) . translate(1.45,.55),

  triangle = { filledPolygon((0,0),(10,0),(10,10)) },
  triangle-outline = { polygon((0,0),(10,0),(10,10)) },
  sample = {
    filledPolygon((0,0),(10,0),(5,5))[#ntColour,#ntColour,#ntColour]
    } transformed by reduce
    + #triangle-outline,
  S = #sample,
  
  f1 = scale(1/3, .5),
  f2 = scale(2/3, .5) . translate(10/3,0),
  f3 = scale(2/3, .5) . rotate(180) . translate(10,5),
  f4 = scale(1/3, .5) . translate(20/3,5),
  F = < f1, f2, f3, f4 >,
  
  g = scale(2/3, .5) . translate(10/3,0),
  G = <f1, f4, { filledPolygon((0,0),(10,0),(10,10), (0,10)) } transformed by g>
  
}
