assign(domain_size,60).  %grid 3x20
assign(max_models,1).
assign(max_megs, -1).
set(arithmetic).

list(distinct).
 [a0,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,a13,a14,a15,a16,a17,a18,a19,
  a20,a21,a22,a23,a24,a25,a26,a27,a28,a29,a30,a31,a32,a33,a34,a35,a36,
                                                            a37,a38,a39,
  a40,a41,a42,a43,a44,a45,a46,a47,a48,a49,a50,a51,a52,a53,a54,a55,a56,
                                                            a57,a58,a59].
end_of_list.

formulas(utils).
  x < 40 -> (on(x,y) <-> y = x + 20).  %x on y, 
  x > 39 -> -on(x,y).                  %3x20 grid
  
  (x != 19 & x != 39 & x != 59) -> (left(x,y) <-> y = x + 1). 
 -(x != 19 & x != 39 & x != 59) -> -left(x,y).                
end_of_list.


