This doesn't actually work if there's no immediate solution and you have to pick duds before you can make progress. But I think the way to brute force that is b

This doesn't actually work if there's no immediate solution and you have to pick duds before you can make progress. But I think the way to brute force that is by breadth-first search for dud-prefixes and ending with the specific sequence searches. For now I fixed it by just assuming we can always solve the puzzle with a single "leap of faith" pick at the start (seems so from my own anecdotal experience?) :) Note that the full puzzle isn't really solvable off-line (edit: I mean in a fully general sense) because of the case where you switch from solving one sequence to another and an extra prefix gets added by the game as a punishment!