Why the sound and the image are not displayed at the same time? HELP!

My code:

import processing.sound.*; //Import sound librarie

// Create a SoundFile
SoundFile sound;
sound = new SoundFile(this, "est.wav");

// Play and show a rect at the same time. PROBLEM
for (int i = 0; i < 10; i++) {
  delay(200);
  sound.play();
  fill(120);
  rect(random(100), random(100), width/2, height/2);
}

Thx!!