The spiral puzzle has been a fixture for puzzle fans for a while. Here's the basic design:
There are two strings of words to fill a spiral with; in the design above, one goes clockwise outward, the other goes counterclockwise inward. I feel like I've seen other designs where the clockwise direction is the one that goes inward, but if so, they don't seem widespread.
I knew early on that I wanted to do something like this for the Ubercross Abecedaria O. But how to stick this in the context of a crossword grid, where everything is all about squares? How to square the circle?
I considered a design that looked like the above (only, you know, scaled up, and solved in two directions instead of just one). But I couldn't get it to play nicely with the design of the giant O. No matter how I tweaked it, it kept looking like what it was: a square peg in a round hole.
So I opted to design some “loops” instead. The final puzzle has four rings of circled letters, two each around the inner and outer border of the O. In each ring, the most northwest point is where the solving starts. From there one string of answers goes clockwise and one goes counterclockwise, which would mean that each square gets used in two different answers even if most of them weren't also interacting with the crossword grid. Though the inward and outward motion of the spiral is gone, the loops preserve the bidirectional aspect, and that's the most important.
Will Shortz, introducer of the form and still probably its biggest booster, provides us an example above. Inward/counterlockwise, the answers are SORT, SIBYL, EVITA, GENTLEMAN, UTERUS, NECTAR, COTS, IRASCIBLE, MARACAS, SENORA, BETTOR, AGASSI, LEMAITRE, NINE-MONTH, GIFT, and ACETIC. Outward/clockwise, they go CITE, CATFIGHT, NOMEN, INERTIA, MELISSA, GAROTTE, BARONESSA, CARAMEL, BICS, ARISTOCRAT, CENSURE, TUNA MELT, NEGATIVELY, BISTROS.
Note that most of these answers are over five letters long, none are under four, and all of them overlap by at least a couple of letters. That’s the master designer at work, making sure that each little victory in the puzzle gives you tools to tackle the next part and keeping the vocabulary rich and interesting. (Even the master’s not immune to the occasional compromise—BARONESSA instead of BARONESS feels a little stretchy. But this is the level to strive for.)
Writing answers in two directions is a fairly constrained exercise. There are a bunch of words like BUNCH that don't work at all in a backwards format, even if you try to divide up the most difficult parts. HCNUB…I could make the end part of NUBIA or NUBILE, but there’s nothing for the beginning that ends with HC. Nothing I'd want to use, anyway.
Still, putting it together was a fun little game, almost because of those constraints. When you only have three options for what the next word is going to be, it can be a lot easier to choose than when you have dozens or hundreds of options.
And it helped get me ready for the next challenge. Usually, each piece of the Ubercross Abecedaria is a clean break from the previous piece. The theme of the M section had nothing to do with the theme of the N section, and the N sections themehad nothing to do with the theme of O. But writing in two directions would be very useful for the theme of P. And I'll talk about that next.