twelve.fzn

array [1..16] of var int: x :: output_array([1..4, 1..4]);
constraint int_le(0, x[1]);
constraint int_le(0, x[2]);
constraint int_le(0, x[3]);
constraint int_le(0, x[4]);
constraint int_le(0, x[5]);
constraint int_le(0, x[6]);
constraint int_le(0, x[7]);
constraint int_le(0, x[8]);
constraint int_le(0, x[9]);
constraint int_le(0, x[10]);
constraint int_le(0, x[11]);
constraint int_le(0, x[12]);
constraint int_le(0, x[13]);
constraint int_le(0, x[14]);
constraint int_le(0, x[15]);
constraint int_le(0, x[16]);
constraint int_lin_eq([1, 1, 1, 1], [x[1], x[2], x[3], x[4]], 5);
constraint int_lin_eq([1, 1, 1, 1], [x[1], x[5], x[9], x[13]], 5);
constraint int_lin_eq([1, 1, 1, 1], [x[4], x[8], x[12], x[16]], 5);
constraint int_lin_eq([1, 1, 1, 1], [x[6], x[7], x[10], x[11]], 0);
constraint int_lin_eq([1, 1, 1, 1], [x[13], x[14], x[15], x[16]], 5);
constraint int_lin_eq([1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1], [x[1], x[2], x[3], x[4], x[5], x[6], x[7], x[8], x[9], x[10], x[11], x[12], x[13], x[14], x[15], x[16]], 12);
solve satisfy;