applications.collages.gridAlgebra:
( 3,
  { E = 1bc-3ab-4ab-5cd-7da,
    F = 0ab-1ab-2bc-3da-4ab-5bc-6da-7cd-8cd,
    G = 2ab-4ab-5ab-6ab-7bc,
    H = 2ab-4ab-8da,
    I = 2ab-4ab-6ab,
    J = 2ab-4ab-5ab-8da,
    K = 5ab,
    S += { polyline((-20,-5),(-5,-20)),
           polyline((5,-20),(20,-5)),
	   polyline((20,5),(5,20)),
	   polyline((-5,20),(-20,5)) },
    A += { polyline((20,-20),(-20,20)),
           polyline((20,-5),(15,0),(20,5)),
	   polyline((5,20),(0,15),(-5,20)) },
    B += { polyline((20,-20),(-20,20)) },
    C += { polyline((20,-5),(15,0),(20,5)),
           polyline((20,-20),(0,0),(20,20)) },
    D += { polyline((20,-20),(0,0),(20,20)) }
  }
)
