let columns, rows;

let board;

let x = 300;

let y =150;

function setup() {

  createCanvas(900, 600);

  columns = width / w;

  rows = height / w;

  board = create2DArray(columns, rows);

  for (let i = 8; i < 42; i++) {

    for (let j = 15; j < 35; j++) {

      board[i][j] = floor(random(2));

    }

  }

}

​

function draw() {

  let next = create2DArray(columns, rows);

​

  // Looping but skipping the edge cells

  for (let i = 8; i < 42; i++) {

    for (let j = 15; j < 35; j++) {

      // Randomly reinitialize some cells

      if (random() < 0.025) { // 1% chance to restart the life of a cell

        next[i][j] = floor(random(2)); // Randomly set to 0 or 1

        continue;

      }

​

      let neighbors = 0;

      for (let k = -1; k <= 1; k++) {

        for (let l = -1; l <= 1; l++) {

          neighbors += board[i + k][j + l];

        }

      }

      neighbors -= board[i][j];

​

      // The rules of life!

      if (board[i][j] == 1 && neighbors < 2) next[i][j] = 0;

      else if (board[i][j] == 1 && neighbors > 3) next[i][j] = 0;

      else if (board[i][j] == 0 && neighbors == 3) next[i][j] = 1;

      else next[i][j] = board[i][j];

    }

  }

​

  // Drawing the cells

  for (let i = 0; i < columns; i++) {

    for (let j = 0; j < rows; j++) {

      if (board[i][j] === 0) {

        fill(255); // White for dead cells

      } else {

        fill(0, 0, 255,25); // Blue for alive cells

      }

      noStroke();

      square(i * w, j * w, w);

    }

  }

  board = next;

​

  noFill()

  stroke(0);

  ellipse(width/2, height/2, x, y);

}

​

function create2DArray(columns, rows) {

  let arr = new Array(columns);

  for (let i = 0; i < columns; i++) {

    arr[i] = new Array(rows);

    for (let j = 0; j < rows; j++) {

      arr[i][j] = 0;

    }

  }

  return arr;

}