Are these crop circles?
At first glance you might think so. This, however, is an aerial photograph of Sun City in the Valley of the Sun. Thousands of houses have been built in this retirement-zoned area just west of Phoenix. What look like crop semi-circles are golf courses.
I recently played a round of golf and one of the residents joined our 3 ball and filled me in on the rules. The local law/rule in the area is that there must be at least one person over the age of 55 living in the house.
This local law (I don't know if it's law or a rule and/or how it is enforced) obviously limits the potential for who will buy one of these houses. It may, however, increase the attractiveness for a wealthier older group of buyers. I have not been able to work out if this has put the house prices above or below the average for the area. An interesting exercise.