Link to source code.

let quads = [];

function setup(){
  createCanvas(800,800);
  append(quads,new SqSample(0,0,width/2,8, color(random(255),random(255),random(255))));
  append(quads,new SqSample(width/2,0.0,width/2,8, color(random(255),random(255),random(255))));
  append(quads,new SqSample(width/2,height/2,width/2,8,color(random(255),random(255),random(255))));
  append(quads,new SqSample(0,height/2,width/2,8, color(random(255),random(255),random(255))));
}

function draw(){
  background(0);
  for(let i = 0; i < quads.length; i++){
    let sq = quads[i];
    sq.display();
  }
}

class SqSample{
  
  constructor( xpos,ypos,size,ct,c ) {
    this.x = xpos;
    this.y = ypos;
    this.w = size;
    this.sc = c;
    this.counter = ct-1;
    this.gs = 0;
    this.gslimit = random(80)+20;
    this.gstop = 0;
  }
  
  display(){
    noStroke();
    fill(this.sc);
    rect(this.x,this.y,this.w,this.w);
    this.gs++;
    if(this.gs > this.gslimit && this.gstop == 0 && this.counter > 0){
      append(quads,new SqSample(this.x,this.y,this.w/2,this.counter, color(random(255),random(255),random(255))));
      append(quads,new SqSample(this.x+this.w/2,this.y,this.w/2,this.counter, color(random(255),random(255),random(255))));
      append(quads,new SqSample(this.x+this.w/2,this.y+this.w/2,this.w/2,this.counter, color(random(255),random(255),random(255))));
      append(quads,new SqSample(this.x,this.y+this.w/2,this.w/2,this.counter, color(random(255),random(255),random(255))));
      this.gstop = 1;
    }
  }
}