There's a lot to optimize here - a bit of looking at the profiler and an 8-line patch makes generating 24-character solutions already 5+ times faster (on my Mac

There's a lot to optimize here - a bit of looking at the profiler and an 8-line patch makes generating 24-character solutions already 5+ times faster (on my MacBook, using a single process). Considering there is no LICENSE in the original notebook or repo, I'm not sure I can publish my changes.