createCanvas(400, 400);

}

​

function draw() {

  background(220);

  stroke(200, 50, 200);

  var cy = height / 2;

  for(var i = 0; i < width; i++) {

    //symetrical noise ( noise(i) == noise(-i) )

    point(i, cy + noise(((width / 2) - i) / width) * 200);

  }

}