let x = 0;

​

function setup() {

  createCanvas(windowWidth, windowHeight);

  frameRate(10);

  nbLines = width*10;

}

​

function draw() {

  background(220, 220, 220, 100);

  stroke(0, 0, 0, 60);

  for(let i = 0; i < nbLines; i++){

    x = x > width ? 0 : x+1;

    line(x, height, x, random(0, height));

  }

}