// as array of color pointer only, and delete the class thing

​

let x = 12, y = x, w = 30, h = w, offset = 2, grid = 15, many = grid * grid;

let mytiles = [];      // array long "many" remember random color pointer only

var mycolors= [[255,0,0],[255,128,0],[255,255,0],[0,255,0],[0,0,255],[127,0,255],[255,102,178],[80,80,80]];      // array of 8 colors

​

function setup() {

  createCanvas(500, 500);

  noStroke();

  for (let i = 0; i < many; i++) mytiles[i]=int(random(8));     // make random tiles color array

//}

//function draw() {     // no need for draw loop now

  background(0);

  draw_myRects();

}

​

function draw_myRects() {

  for (let i = 0; i < many; i++) {

    let posx = x + (i % grid) * (w + offset);

    let posy = y + (floor(i / grid)) * (h + offset);

    fill(mycolors[mytiles[i]][0],mycolors[mytiles[i]][1],mycolors[mytiles[i]][2]);

    rect(posx, posy, w, h);

  }

}

​