createCanvas(600, 500);

  background(20);

  angleMode(DEGREES);

  noLoop();

}

​

function draw() {

  // stroke(150, 150, 0, 100);

  strokeWeight(6);

​

  for (let i = 0; i < 20; i++) {

    let x = random(50, 500);

    let y = random(240, 490);

    tree(x, y, 0, 8);

  }

}

​

function tree(x1, y1, angle, depth) {

  stroke(depth * 5, depth * 40, depth * 5, 200);

  strokeWeight(depth / 2 + 0.2);

​

  let r = int(random(4));

​

  let length = 40 * Math.tanh(depth / 4) * r/2;

​

  let x2 = x1 - length * sin(angle);

  let y2 = y1 - length * cos(angle);

​

  let x3 = x1 - 0.7 * length * sin(angle);

  let y3 = y1 - 0.7 * length * cos(angle);

​

  let x4 = x1 - 0.4 * length * sin(angle);

  let y4 = y1 - 0.4 * length * cos(angle);

​

  line(x1, y1, x2, y2);

​

  let angle1 = angle + 20 + random(-15, 15);

  let angle2 = angle - 20 + random(-15, 15);

​

  if (depth > 1) {

    tree(x2, y2, angle1, depth - 1);

    tree(x2, y2, angle2, depth - 1);

    if (r > 2) {

      tree(x3, y3, angle1, depth - 1);

    }

    if (r > 1) {

      tree(x4, y4, angle2, depth - 1);

    }

  }

}

​