// https://editor.p5js.org/codingtrain/sketches/Zs65bV-Al

​

let x, y;

let px, py;

let step = 1;

let stepSize = 90;

let numSteps = 1;

let state = 0;

let turnCounter = 1;

let totalSteps;

​

function isPrime(value) {

  if (value == 1) return false;

  for (let i = 2; i <= sqrt(value); i++) {

    if (value % i == 0) {

      return false;

    }

  }

  return true;

}

​

function setup() {

  createCanvas(600, 600);

​

  const cols = width / stepSize;

  const rows = height / stepSize;

  totalSteps = cols * rows;

​

  x = width / 2;

  y = height / 2;

  px = x;

  py = y;

  background(0);

}

​

function draw() {

  textSize(stepSize*0.5);

  textAlign(CENTER, CENTER);

  fill(255);

  //stroke(255);

  noStroke();

  text(step, x, y);

  stroke(255);

  strokeWeight(0.5);

  noFill();

  rectMode(CENTER);

  rect(x,y,stepSize);

  // if (isPrime(step)) {

  //   circle(x, y, stepSize * 0.5);

  // }

  // line(x, y, px, py);

  px = x;

  py = y;

​

  switch (state) {

    case 0:

      x += stepSize;

      break;

    case 1:

      y -= stepSize;

      break;

    case 2:

      x -= stepSize;

      break;

    case 3:

      y += stepSize;

      break;

  }

​

  if (step % numSteps == 0) {

    state = (state + 1) % 4;

    turnCounter++;

    if (turnCounter % 2 == 0) {

      numSteps++;

    }

  }

  step++;

​

  // if (step > totalSteps) {

  //   noLoop();

  // }

​

  //frameRate(1);

}

​