Behold a sweet animated .gif that I stole from Wikipedia. Sometimes, I wish I had special vision, like seeing in time-lapse (also, I would like telescopic binocular vision). Seeing in time-lapse would be a step toward seeing in the 4th dimension, which was written about in a cherished Vonnegut book, "Breakfast of Champions." Although in the book, a man's genitalia was referred to being seen in the 4th dimension, not the Moon.
In all honesty and seriousness and scientificness, the motion of the Moon is interestingly complex, as I've discovered for myself recently. Thanks again, Wikipedia! We can attribute the Moon's difference in size throughout the lunar month to its elliptical orbit around the Earth and we can thank the iron-rich, basalt-filled maria (seas...the dark patches on the Moon) for the differential in mass throughout the lunar "sphere." Gravity's action on that differential causes us to see that denser "face" of the Moon more or less perpetually.
There are other things like libration, nodal precession, and a ~5° orbital-plane-inclination-to-the-ecliptic that I can mention as well, but that's too much analysis, I think, even for my obsessive interest. These are ideas, mainly, that don't make much sense because they're incredibly hard for most of us to actually visualize. I find that images like this .gif really unlock the understanding of astronomical phenomena that require - in most cases - extremely long amounts of time to transpire. Most of the time, for most of us, simply "pondering the heavens" isn't enough to comprehend their true nature. Pictures help, and I am on the lookout for more of these!
