applications.collages.gridAlgebra:
( 3,
  {
    F = 0ab-1bc-2ab-3bc-4bc-5bc-6ab-7bc-8ab,
    G = 0ab-2ab-3ab-5ab-6ab-8ab,
    S += { 
        filledPolygon((-20,-8),(20,-8),(20,-5),(-20,-5)),
        filledPolygon((-20,8),(20,8),(20,5),(-20,5)),
        filledPolygon((-8,-20),(-5,-20),(-5,-7),(-8,-7)),
        filledPolygon((8,-20),(5,-20),(5,-7),(8,-7)),
        filledPolygon((-8,20),(-5,20),(-5,7),(-8,7)),
        filledPolygon((8,20),(5,20),(5,7),(8,7)),
        filledPolygon((-20,-20),(-17,-20),(-17,20),(-20,20)),
        filledPolygon((20,-20),(17,-20),(17,20),(20,20))
      },
    A += { 
        filledPolygon((-8,-20),(-8,20),(-5,20),(-5,-20)),
        filledPolygon((8,-20),(8,20),(5,20),(5,-20)),
        filledPolygon((-20,-20),(-20,20),(-17,20),(-17,-20)),
        filledPolygon((20,-20),(20,20),(17,20),(17,-20))
      }
  }
)
