I know, I know. Just like me, through Google Books, you found Stephen Sondheim's "Code I" puzzle in the May 12, 1969 issue of New York Magazine. But the encoded clue for 16 Down doesn't make sense! Sure, you checked the solution to the puzzle, as printed in the June 2, 1969 issue. And okay, while the solution acknowledges the error — "Apologies for the letters omitted from the clue for 16 Down" — it doesn't say what the missing letters are! And to make matters worse, the mistake wasn't even corrected for publication in the book Stephen Sondheim's Crossword Puzzles!
No problem. I figured it out. It was not easy, oh no, it was not easy, and so I'm going to say it again in all caps: I FIGURED IT OUT. (I used Adobe InDesign to solve it. No joke.)
16 Down isn't:
HINETAG LSIHNGT HNOSAKSH EOFGITNP ONFOAHYI
It's:
HINETAG LSIHNGT HSTIW NNOSAKSH EOFGITNP ONFOAHYI
There. You're welcome. I feel certain this post will be the one to skyrocket my blog to the heights of popularity in the blogosphere.