createCanvas(400, 400);

}

​

function draw() {

  background(220);

  // draw lots of vertical lines

  // if i is less than width, increase i by 10

  for(let i = 0; i < width; i+=10){

    // i is equal to 0, 10, 20, 30, 40, 50, 60, 70, etc...

    line(i, 0, i, i);

  }

}