Friday, September 23, 2021 - Enjoy Your LEAPDAY

From Jean & Mike Do The New York Times Crossword MP

A gentle Friday, Jean did it in slightly less time than usual, whereas Mike cleaved off 3h5m (if only we were kidding!) from his cataclysmically bad Thursday time. Jean started off slowly and picked up steam as she went along; Mike found most of the puzzle firmly planted in his wheelhouse, with the exception of the top-right corner (with 16A, Lustrous shell compound, NACRE, and 10D, What genes do, biologically, ENCODE (not, with apologies to biology teachers everywhere, DIVIDE), causing...