let cols = 0;

let blocks = [];

let w = 40;

let h = w;

​

function setup() {

  createCanvas(600, 400);

  rows = height / h;

  cols = width / w;

​

  for (let i = 0; i < cols; i++) {

    blocks[i] = [];

    for (let j = 0; j < rows; j++) {

      blocks[i][j] = new Block(i * w, j * h, w, h);

    }

  }

}

​

function draw() {

  background(0);

  for (let i = 0; i < cols; i++) {

    for (let j = 0; j < rows; j++) {

      blocks[i][j].show();

    }

  }

}