[decimalBullet, alphaBullet, romanBullet, decimalBullet, alphaBullet, romanBullet];

function addStepNumberText(ol, parentIndex) {
  for (let i = 0; i < ol.children.length; ++i) {
    let child = ol.children[i];
    let index = parentIndex.concat([i]);
    let applicable = bullets[Math.min(index.length - 1, 5)];
    let span = document.createElement('span');
    span.textContent = (applicable[i] || '?') + '. ';
    span.style.fontSize = '0';
    span.setAttribute('aria-hidden', 'true');
    child.prepend(sp