(* A curva de hilbert
     ver https://en.wikipedia.org/wiki/Hilbert_curve
*)

def l(n) {
  if n {
    turnright 90
    r(n-1)
    forward 8
    turnleft 90
    l(n-1)
    forward 8
    l(n-1)
    turnleft 90
    forward 8
    r(n-1)
    turnright 90
  }
}

def r(n) {
  if n {
    turnleft 90
    l(n-1)
    forward 8
    turnright 90
    r(n-1)
    forward 8
    r(n-1)
    turnright 90
    forward 8
    l(n-1)
    turnleft 90
  }
}

penup
forward -250
turnleft 90
forward -250
pendown
l(6)