melanie animation

var timer = 0;

var leaf = createSprite(175, 166);
leaf.setAnimation("leaf");
leaf.visible = true;
leaf.scale = 4;

var caterpillar = createSprite(200, 200);
caterpillar.setAnimation("caterpillar");
caterpillar.visible = false;
caterpillar.scale = 4;

var sac = createSprite(200, 200);
sac.setAnimation("sac");
sac.visible = false;
sac.scale = 4;

var butterfly = createSprite(200, 200);
butterfly.setAnimation("butterfly");
butterfly.visible = false;
butterfly.scale = 4;

function draw() {
  timer = timer + 1;
  if (timer < 30) {
    leaf.visible = true;
  }
  if (timer >= 60) {
    leaf.visible = false;
    caterpillar.visible = true;
  }
  if (timer >= 90) {
    caterpillar.visible = false;
    sac.visible = true;
  }
  if (timer >= 120) {
    caterpillar.visible = false;
    butterfly.visible = true;
  }
  drawSprites();
}