createCanvas(800, 600);

  background(220);

  angleMode(DEGREES);

  noLoop();

}

​

function draw() {

  let stepSize = 25;

  let turtleX = 400;

  let turtleY = 200;

  let turtleAngle = 0;

​

  strokeWeight(1);

  stroke(255, 0, 0, 100);

​

  let code = [..."FRFLF"];

  let nextGenCode = [];

  let generations = 5;

​

  for (let genNum = 1; genNum <= generations; genNum++) {

    nextGenCode = [];

    for (let instruction of code) {

      if (instruction == "F") {

        nextGenCode.push(..."RF[RFLFL]F");

      } else {

        nextGenCode.push(instruction);

      }

    }

    code = nextGenCode;

  }

​

  let notebook = [];

​

  for (let instruction of code) {

    if (instruction == "F") {

      let newX = turtleX - stepSize * sin(turtleAngle);

      let newY = turtleY - stepSize * cos(turtleAngle);

      line(turtleX, turtleY, newX, newY);

      turtleX = newX;

      turtleY = newY;

    }

    if (instruction == "L") {

      turtleAngle += 40;

    }

    if (instruction == "R") {

      turtleAngle -= 20;

    }

    if (instruction == "[") {

      notebook.push(turtleX);

      notebook.push(turtleY);

      notebook.push(turtleAngle);

    }

    if (instruction == "]") {

      turtleAngle = notebook.pop();

      turtleY = notebook.pop();

      turtleX = notebook.pop();

    }

  }

}

​