5D: If you’ve been to an enormous waterfall, like Victoria (above) or Niagara, you’ve probably seen signs for CATARACTS. The word originates from Greek and Latin for a “furious rush of water,” so it makes sense as a synonym. In Latin, there’s an alternate meaning of “portcullis,” which helps explain why an eye condition goes by the same name. Over time, the erosive effects of rushing water often carve caves and indentations from the rock walls behind the falls that are great for hiding treasure in.

9D: This is a cool factoid that comes around every so often for a common bit of geographical fill: AMMAN, the capital of Jordan. Amman has had many incarnations since 3500 B.C., whence its earliest known relics come, including a lengthy period as “Philadelphia” in honor of an actual person, Ptolemy Philadelphus (also B.C.). Philadelphia, Penn., on the other hand, was so named because Philadelphia is a rough translation of “brotherly love.”

16D: Ms. Gray owns a landscaping business (per Will Shortz’s introduction to the print version of this puzzle), which explains the generous handful of horticultural references today. There are so many feminine names that are flowers — we know Daisies, Roses, Petunias, and even a flower used elsewhere in the grid, VIOLETS. “Fragrant” is a useful hint; Jasmine came to mind, which is a popular girl’s name in its own right, and easily mutates to YASMINE.

Today’s Theme

There are seven shaded/bubbled down entries in the grid today, three or four letters in length, that form a word running backward as well as forward. Each of them “ends” (if you go with gravity, or read them forward) by crossing the first or last letter of an across entry that goes along with it — and that across entry has a clue that requires you to combine the shaded/bubbled down entry with the across entry it runs into.

Clear as mud, eh? Fortunately for all of us, the complexity of the setup is manifested very elegantly and lightly, so as not to be an exercise in befuddlement. The length and simplicity of the down entries is key here, but the fact that the end result is still challenging, and still feels gratifying to figure out and worthwhile to complete, is really a testament to very skillful construction.

Let’s take a look at 39A, which relies on the shaded entry at 24D to make the theme, and was tight and good, not at all obscure. 24D, “Cheese with a red covering,” is a classic clue for a bit of classic crossword fill, EDAM — it’s been clued this way since 1950.