Puzzilla.org is now Tree Access Certified by FamilySearch.org. Here is a quote from the announcement:
Looking for new relatives to take to the temple? Is your pedigree picked over? Is there really no work left for you and your family to do? The Puzzilla.org Descendants Viewer lets you see hundreds of descendants of your ancestors from an aerial view using compact symbols to reveal patterns of incomplete research. You can pick up where prior research left off. Click on a pedigree ancestor and Puzzilla will show you their descendants, revealing holes where research might uncover spouses, children, and generations of relatives waiting for you to find them.Here is another screen shot after having chosen one of my ancestors and showing the descendants. Each of the dots represent an individual descendant of my remote ancestor James Parkinson. Using this graphic representation of the family lines available in Family Tree, it is amazingly simple to find lines which have no representation in Family Tree.
You absolutely need to try out this fabulous addition to Family Tree. If you don't get what it is trying to show you, just take time to watch the introductory videos and play around with the program. You will soon get the idea and see the value of having a graphic display that shows you places where Family Tree needs additional information.