petroglyph

A petroglyph emerges from the sands of the Sahara in Chad.

这是非洲乍得境内大沙漠里的一块岩石画。

It resembles a petroglyph of some sort more than it resembles the "usual" crop circle design.

与其说它像“普通的”麦田怪圈，如说它有点像某种岩石雕刻。