p5js--coloresSquares

//change framerate and thereby the speed of the squares to appear
speed=30;
alph=1;


function setup() {
  createCanvas(600,500);
  background(0);
  frameRate(speed);
}

function draw() {
   x=random(1,width);
  y=random(1,height);

  r=map(x,0,width,0,255);
  b=map(x,0,width,255,0);
  //g=map(y,0,height,255,0);
  g=0;
  noStroke();
  fill(r,g,b,alph);
  rect(x,y,40,40);
  alph+=1/10;
}