applications.collages.collageAlgebra:
{  
  line = { polyline((0,0),(2,0))<0,0,0> width .01},
    
  f0 = scale(.707) . rotate(-45) . scale(1,-1),
  f1 = scale(.707,-.707) . rotate(-45) . translate(1,1),
  F = < f0, f1 >,
  
  col1 = colourOperation(r|1/2:0,b|1/2:1),
  col2 = colourOperation(r|1/2:1,b|1/2:0)
  
}
