why did we spend a year making 7x7 puzzles?
When you make crosswords, there are certain rules you follow. (Not all of the time! But most of the time.)
These are the rules:
BUT! Let's say we do follow all these rules. Then there are exactly 312 possible 7x7 puzzle grids you can form.
312 is a cool number because it's 6 x 52. In other words, if you published six puzzles a week, it would take exactly a year to try every possible 7x7 grid. So, here we are!
There's a good write-up of the crossword puzzle problem here, and a description of how to solve it for 15x grids here.