Почему в js не добавляется пробел?

const out4 = document.querySelector('.out-4');

function f4() {
    let a4 = '';

    for (let a = 3; a > 0; a--) {
      if (a == 3) {
        a4 += '  ';
      } else if (a == 2) {
        a4 += ' ';
      }

        for (let b = 0; b < 5; b++) {
            a4 += '*';
        }
        a4 += '<br>';
    }
    out4.innerHTML = a4;
}
document.querySelector('.b-4').onclick = f4;

body {
  margin: 0;
  padding: 0;
}

<section class="section-4">
   <p>TASK 4</p>
   <button class="b-4">Пуск</button>
   <div class="out-4"></div>
</section>
<p> Lorem ipsum, dolor sit amet consectetur adipisicing elit. Quam blanditiis, mollitia possimus officia hic repudiandae dolore accusamus, expedita cupiditate nihil molestiae ad molestias, tenetur laudantium magnam praesentium illum debitis nam!</p>