THIRTY! THIRTY! THIRTY! THIRTY! THIRTY! THIRTY! THIRTY!
Echoes are fun.
Today I celebrate my thirtieth birthday - a fitting day to publish Puzzle 30, which happens to be a 30×30 grid with another rather auspicious '30' in it. Before anyone asks, yes, I tried scaling this one up to 600×600 like all the others; trust me, it wasn't pretty. What lies below is the actual original image in its native size - 475×475.
See Puzzle 3 for instructions. This may well be the most challenging-to-solve puzzle I've yet presented here. Hopefully it will make up for the last two and then some. I pulled out practically every trick I know. This puzzle can be solved purely deductively without guessing (structured or otherwise - put that thread away), but it will take a solid understanding of the design's mechanics to do so. Actually, I'm disappointed: the particular technique I was happiest to utilize turns out to be unnecessary - sequence-broken, to borrow the videogaming term. However, it could still be found and serve to speed things up, and there are plenty of other tricks to go around, so I'm happy with the puzzle as a whole. Your mileage may vary; by all means, let me know what you think of it. I await your solutions, and I have a rather fitting prize in mind I may be awarding... - ZM