From Cabel Sasser on Twitter:

And thanks to the Apple person who added this "floor crosshair" feature to iOS 11 for perfect face-down junk food shots!! That was the goal pic.twitter.com/fA5oobTdcN

— Cabel Sasser (@cabel) November 7, 2017

First things first, this is a great new feature. To see it for yourself, go to Settings > Camera, and make sure that Grid is enabled.

Now, when you tilt your camera flat and facing the floor (or, interestingly, the ceiling), a crosshair will appear.

But what really struck me was reading the replies to the thread, where the Apple developer who created the feature as an intern chimes in. For all its faults, this is the gold heart of Twitter.