Task-1: All p tags that have no children, but only if they don't have a class of ignore.
Task-2: Any element with the text "REPLACE_ME" in it.
Task-3: All div tags with a child that has a class of special.
Task-4: All heading elements (h1, h2, h3, h4, h5, h6).
Task-5: Every other visible li.
Task-6: Use the DOM API to target the #square and periodically change it's position in a random direction.