Many are designed to gradually dissolve into the landscape. But while they last, they're cool to contemplate.
One example is Sarah Vanderlip's "untitled," a silvery lozenge that looks like a titanium dinosaur egg nestled among the rocks.
To find it, look for the big yellow BAIL BONDS sign 1 mile east of downtown Joshua Tree, then head to the end of Neptune Street.
In honor of this year's National Park Service centennial, the Travel section is posting 100 park travel ideas and tips based on trips staff travel writer Christopher Reynolds has taken, along with photo-op advice from Times photographer Mark Boster. We'll post one per day through Dec. 31.
Follow Reynolds on Twitter: @MrCSReynolds