queens_naive(N, Q) =>
  Q = new_list(N),
  Q :: 1..N,
  foreach(I in 1..N, J in 1..N, I < J)
    Q[I] #!= Q[J],
    Q[I] + I #!= Q[J] + J,
    Q[I] - I #!= Q[J] - J
  end,
  solve([ff], Q).