Anil Gangolli writes about OMBY:

I’m not sure to whom to attribute this nicety in OMBY (Thane or Greg), but QUEEQUEG appears in one row of many of the OMBY puzzles, and the sequence of tiles forming “QUEEQUEG” has 24 (2!x2!x3!) spelling-invariant permutations, leading to little secondary puzzles in the other row. Straightening “STARBUCK”, when appearing in similar circumstances, however, reveals all.

I wish we could take credit for this, but – like so many things in this project – it just fell out. We did spend a lot of time optimizing the puzzle selections for other metrics, just not this one. We’ll have to give the credit to Melville, or maybe to Thane for suggesting Moby-Dick in the first place!

Out of curiosity, I went back and computed the spelling-invariant permutations for solved lines in all of the puzzles… QUEEQUEG is a good one, especially because it’s so likely to jump out when you see those letters, but it’s not the hardest by this metric. We also have puzzles with ACCOMMODATED (32 permutations) and INSIGNIFICANT (144 permutations) and LANDLESSNESS (192 permutations)… and, if you’re willing to consider multiple word lines, the hardest of them all is SEEM TO SEE OF (576 permutations).