Neat bit of trivia: the Shortz era began with a great tribute to ROY G. BIV, the colors of the rainbow, in order. This theme concept has been revisited many a time — such great crossword fodder.
It is, however, difficult to fit in all seven colors into a 15x15 grid. (The average number of themers is about five these days.) Michael and Acme accomplish it today, and also stick in RAINBOW as a revealer. Impressive to work in eight themers, fairly smoothly.
Excellent use of interlock, INDIGO GIRLS crossing BLUEBIRDS, and YELLOW LIGHT crossing VIOLET RAY. In some cases, constructors use this sort of interlock to show off, more for themselves than for the solver. But here, it's almost necessary, to squeeze everything in. I highlighted the themers below, to demonstrate how tight a fit it is.
Oh, if it hadn't been for VIOLET RAY — all the other themers are so colorful (ha ha). What a curious grid entry. (I usually see SHRINKING VIOLET for this theme type.) It was interesting to learn about this antique piece of medical equipment, but electrotherapy seems so barbaric.
It's tough for a science nerd like me to see all the colors spread out willy-nilly, instead of in proper ROY G. BIV order. I'm not entirely sure it could have been done without more compromises (LIII, ITI, ACS — I ASEA you), but here's one case where I would have been okay with a higher price to pay in order to get proper color order.
THINGS NEED TO BE PROPER, SHOUTED THE OCD DORK!
My poor kids.
Hear me out. Put RED TAPE in row 3, all the way to the left. ORANGE PEEL all the way to the right, in row 4 or 5. Keep alternating until you reach RAINBOW, down in row 13. Or take out RAINBOW if you need to.
Heck, even if you needed to go asymmetrical, I'd accept that. ANYTHING TO ACHIEVE ORDER! THE WILLY-NILLINESS IS SO DISTRACTING!
I should probably find them a therapist sooner rather than later.
But overall, still an impressive feat to fit eight themers in. If in a disorderly fashion.