function setup() {

  createCanvas(800, 400);

  colorMode(HSB);

  bottomColor = color(10, 128, 128);

}

​

function draw() {

  background(220);

​

  beginShape();

  vertex(0, height);

  fill(hue(bottomColor), 255 * 0.2, 255 * 0.7, 200);

  for (let x = 0; x < width; x++) {

    //var angle = map(x, 0, width, 0, TWO_PI);

    let angle = x * 0.1;

    // map x between 0 and width to 0 and Two Pi

    let y = map(abs(sin(angle)), 0, 1, 0, 10);

​

    let angle2 = x * 0.01;

    let y2 = map(sin(angle2), -1, 1, 0, 30);

    y += y2;

​

    let nx = map(x, 0, width, 0, 3);

    //y += 50 + 60 * noise(nx);

    vertex(x, height - y);

  }

  vertex(width, height);

  endShape();

}