New York Times, Thursday, December 19, 2013

Thousands of University of Minnesota students learning organic chemistry have read George's handout that reveals the four secrets of organic chemistry, the second of which is that "oil and water don't mix." Back in the spring of 2006, we were brainstorming in our usual ways via e-mail, IM chat, and occasional phone calls, and realized that LIKE_OIL_AND_WATER was 15 letters and could span the center of a grid. Recalling that the majority of organic liquids are less dense than water and hence form an upper phase after being shaken with water, it occurred to us to place oil-containing theme entries exclusively above the central entry, and water-containing entries exclusively below.

Early decisions were to have OIL and WATER both be rebuses (for a while we toyed with HHO or even HOH, but those ideas proved unworkable), to use left-right symmetry, and to separate the two phases by a staggered set of solid bold bars rather than full-sized blocks. Mike ran the concept by Will informally, but the project went into hibernation for several years until the summer of 2010. It was then that Mike realized that switching the positions of the words OIL and WATER in the central reveal would also allow a vertical T(oil)ET(water) entry to place rebus elements both above and below the divide.

Mike produced a few candidate grids that we worked together to polish over the next few months, and George saw how the word LAYER could be inserted near the lower bottom and could be clued to provide a final level of reveal. Will was hesitant for a long time, because he had never previously used bars in a Times weekday crossword, and he was also concerned about on-line solving. With hindsight, this delay turned out to be a positive, because so many other brilliant constructions that "push the envelope" have been published between the time our original ideas were formulated and the present day. For the two of us, this was a fun collaboration that played into our respective strengths, and we hope that solvers will like it too.

This puzzle is best appreciated in print form, which I hope most solvers use. We did, however, find a workaround for those who have no choice but to solve electronically. As far as I know this is the first Times crossword ever to use heavy bars to separate words in the grid. The two constructors collaborated on it entirely by email. George lives near Minneapolis, Michael in Baltimore.

Whew! Once in a while a puzzle comes along to break all sorts of conventions, and one way or another, it stimulates creativity through both strong positive and negative reactions. Who knows if today's will be looked upon ten years from now as the one that spawned an entire movement using heavy bars? Jim and I (mostly Jim) fixed up the puzzle to reflect the print version, as the Across Lite file seemed not nearly as elegant as print. Hopefully the time Jim and I (okay, 99.9% Jim) spent gives you a nice post-solve experience. And make sure to try the special HTML 5 online solving tool Jim programmed! Or if you're on an iPad or iPhone, you might try out Puzzazz's app.

I enjoyed the idea behind this one, seeded by oil and water not mixing. Perfect for George, who's a professor of chemistry! I had a very rough time with the central entry, because I dropped in LIKE OIL AND WATER with just a few letters and refused to believe it could be anything else. "LIKE WATER AND OIL" actually googlizes better than "LIKE OIL AND WATER" so perhaps this was just my issue (I was glad to hear that George and Michael actually started with OIL AND WATER, which makes me feel less crazy). Also possibly just my issue: the way the top and bottom interlocked, it felt like the oil and the water halves actually *were* mixing (in the central row). Hmm.

Very tough to pull off this construction. Not only do you have the unusual quasi-non-mixing of the top and bottom halves of the puzzle, but there's the rebus factor. George and Michael do well in some of those entries, the lovely HOT WATER BAG and ET VOILA, notably. Rebus entries work best for me when they allow the constructor to work in something unusual, something not typically seen in normal puzzles. But with dense rebus puzzles (or rebus puzzles with high additional constraints), some entries suffered. LOW WATER sounds a bit funny to my ear, and eau de toilette is so much more elegant than TOILET WATER and its slight ick factor.

Lots of good long fill in this one, and the highlight of the puzzle for me: the wonderful clue on MAITRE D'. I was stuck on "two-seater" as a type of car, and was so frustrated I couldn't work my way into that section. But when MAITRE D' (which already looks awesomely weird as an entry) appeared, what a sense of relief + the pleasure of experiencing a great clue. Well done.

This is the first NYT daily crossword to use heavy bars to separate answer words. Across Lite can't handle this so most other solving software uses circled squares with combined and renumbered clues. Just to prove it can be done better, XWord Info has created a special HTML 5 solving experience that duplicates the intended effect.