The New York Times Crossword yesterday (9/11/22) had a clue referencing Houdini's Walking Through A Brick Wall illusion. This caused a surge of traffic to this post from 2014. However, as I didn't reveal the secret, I don't think that post would have been any help.
If you want the answer, you can find it here.
Thanks to Matt Guzman and Diego Domingo for the alert.