let spread;

​

function setup() {

  createCanvas(400, 400);

  background(200)

  spread = width

  stroke(255);

}

​

function draw() {

  background(0);

  let a = 0.0;

  let inc = TWO_PI / spread;

  for (let i = 0; i <= spread; i++) {

    let n = noise(offset+i/100)*100

    let lineHeight = ((1 - sin(a + PI / 2)) * n)

    line(i, height - lineHeight, i, height);

    a = a + inc;

  }

  offset += 0.1;

}