function toggleSet(number) {
  var list = document.getElementById('list-'+number);
  var arrow = document.getElementById('arrow-'+number);

  if (arrow.alt == "right-arrow") {
    arrow.src="/images/arrow-down.gif";
    arrow.alt="down-arrow";
  } else {
    arrow.src="/images/arrow-right.gif";
    arrow.alt="right-arrow";
  }

  Effect.toggle(list,'BLIND',{duration:.25});

  return false;
}