applications.collages.collageAlgebra("arrowhead algebra"):
{
  tip = const(sqrt(3)*5),

  line = { filledPolygon((0,0),(1.1547,-2),(8.8453,-2),(10,0),(8.8453,2),(1.1547,2))<.5,.5,0> },
  
  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 >,
  
  c1  = colourOperation(r|2/3:0, g|2/3:1),
  c2  = colourOperation(r|2/3:.5,g|2/3:.5),
  c3  = colourOperation(r|2/3:1, g|2/3:0)
  
}
