Gravity Defying Land Art... WHOAAAAAA

Yes you read that right, gravity defying land art.  I saw that title and thought "welp, I know what has to make an appearance in my blog next."  Finally, here is the link so you know what I am talking about.  As a basic intro, land art is land that, well, incorporates the land in some way shape or form into its design.  Generally, I am not a huge fan of this type of art because there are already so many artistic beauties in nature.  This however changes everything, from the floating branch doorways in the forest, to my personal favorite of the snowball archway.  Though it does not explain the process to achieve these incredible works, I speculate that there is a very thin string to which the pieces are connected (or some kind of support that blends in with the environment surrounding it.  Again, I am never the biggest fan of land art, but the bizarre and "wow" factors about each piece have won me over enough to consider writing about them.  If things like this could exist in real life without any alteration or fabrication, people would have to re-evaluate everything (gravity woks... but does not work all the time...this could be a problem).  Anti gravity art, redefining logic one leaf at a time.  Are there already existing artworks like this out there?  A "snowballs" chance.  However I still feel very strongly that these works promote the name of land art in a positive way.