Crop Circles

It's round. Flat. Looks like something landed there and burned the grass right off. No new growth.

A Crop Circle?

No, the location of the old backyard trampoline.

What grass there was, had grown to the level of the underside of the tramp. Unused for over a year, it was time to take it down.

After the new sprinklers are installed, it'll likely still be visible - the best part of the lawn will be the old UFO site.