Anyone know what the deal is with these rocks?

At the end of February, we noticed this strange rock thing — arrangement? sculpture? — in the dirt beside Monroe Street in the far northeast corner of Kendall Yards. The snow accentuated a deliberate circular pattern that otherwise might have blended in with the scattered dirt and rocks. This was during the time when everyone was obsessed with True Detective, which lent it a vaguely creepy feel. But it's quite geometric, almost like a sundial or mini-Stonehenge.

We moved on and forgot about it. But then, this week, a similar arrangement appeared in the dirt along Summit Parkway, just west of the Monroe Street Bridge. Some of the rocks are pretty large, but it could be the work of bored kids. Maybe someone’s project while they wait for the bus along Monroe. Anyone know? Any theories?