Crop Circles

Our neighbors have had a little above ground pool in the back yard for at least 2 months. They swam in it at first but then not for quite some time. Eventually they got around to cleaning it out (I think it was growing red algae) and then moved it to give the grass a break. If you ask me, they should have moved it a little sooner.
Not that I have room to say anything, we have at least 3 rectangular spots in our back yard due to the same problem.