distance = 50,

  recNumbers = [5],

  running = false;

​

function setup() {

  createCanvas(windowWidth, windowHeight);

  begin();

}

​

function draw() {

​

}

​

function keyTyped() {

  if (key === 'n' && !running) {

    running = true;

    translate(width / 2, height / 2);

    Collatz();

    for (var i = 0; i < numbers.length; i++) {

      var lastNumber;

      if (numbers[i] % 2 == 0) {

        lastNumber = numbers[i] / 2;

      } else {

        lastNumber = (3 * numbers[i]) + 1;

      }

      var index = recNumbers.indexOf(lastNumber),

        x = distance * cos(i * (TWO_PI / numbers.length)),

        y = distance * -sin(i * (TWO_PI / numbers.length)),

        xPast = (distance - 10) * cos(index * (TWO_PI / recNumbers.length)),

        yPast = (distance - 10) * -sin(index * (TWO_PI / recNumbers.length));

      strokeWeight(2);

      if (numbers[i] % 2 == 1) {

        stroke(255, 0, 255);

      } else if (numbers[i] % 3 == 1) {

        stroke(0, 255, 0);

      } else if (numbers[i] % 3 == 2) {

        stroke(0, 0, 255);

      } else if (numbers[i] % 3 == 0) {

        stroke(255, 0, 0);

      }

      line(x, y, xPast, yPast);

    }

    running = false;

  } else if (key === 'r' && !running) {

    running = true;

    numbers = [32, 5];

    distance = 50;

    recNumbers = [5];

    begin();

    running = false;

  }

}

​

function Collatz() {

  recNumbers = numbers;

  var newNumbers = [];

  for (var i = 0; i < numbers.length; i++) {

    if (numbers[i] % 6 == 4) {

      newNumbers.push(2 * numbers[i]);

      newNumbers.push((numbers[i] - 1) / 3);

    } else {

      newNumbers.push(2 * numbers[i]);

    }

  }

  numbers = newNumbers;

  distance += 10;

}

​

function begin() {

  background(0);

  translate(width / 2, height / 2);

  strokeWeight(1);

  stroke(255);

  fill(255, 255, 255, 75);

  circle(0, 0, 80);

  noFill();

  circle(0, 0, 60);

  circle(0, 0, 40);

  circle(0, 0, 20);

  strokeWeight(3);

  point(0, 0);

  strokeWeight(1);

  line(50 * cos(0), 50 * sin(0), 40 * cos(0), 40 *

    sin(0));

  line(50 * cos(PI), 50 * sin(PI), 40 * cos(PI), 40 *

    sin(PI));

}