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

  line = { polyline((-1,0),(1,0)) },
    
  r1 = translate(1,0) . rotate(30) . scale(1/sqrt(3)) . translate(-1,0),
  r2 = rotate(90) . scale(1/sqrt(3)),
  r3 = translate(-1,0) . rotate(30) . scale(1/sqrt(3)) . translate(1,0),
  refine = < r1, r2, r3 >,
  
  inv = scale(sqrt(3)) . rotate(-90),
  invert = <inv>,
  
  o1 = translate(1,0) . rotate(30) . scale(1/sqrt(3)) . translate(-1,0),
  o2 = translate(-1,0) . rotate(150) . scale(1/sqrt(3)) . translate(0,1/sqrt(3)),
  O = < o1, o2 >,
  
  c1 = scale(1),
  c2 = rotate(180),
  C = < c1, c2 >
  
}
