I strongly disliked the puzzles that quickly devolved to correctly handling a ton of corner cases. 15 and 17 were both in this category. What's the fun in that?

I strongly disliked the puzzles that quickly devolved to correctly handling a ton of corner cases. 15 and 17 were both in this category. What's the fun in that? This is like the boring part of being a developer. Without the payment that goes with being a developer.