Today I’m releasing Fill Harmonics, a music machine that takes its rules and styling from the world of crossword puzzles. The name is a pun: in crossword lingo, “fill” is the stuff that goes into the grid. This project is a collaboration with Natan Last, one of my cruciverbal inspirations and the author of “Across The Universe,” a very fun upcoming book on the history and culture of crosswords (available for pre-order now!).