## Puzzle 77 (Double Back)

This is a Double Back puzzle.

Puzzle 77

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### 2 Responses to “Puzzle 77 (Double Back)”

1. Andy Says:

Continuing my trip through Double Backs of the Past, 95 is the last stop, snif!

I really like puzzles like this which are comprised of many smaller puzzles, partially solvable alone, but partially dependent on global connecting logic. Two other examples that come to mind are the terrific 2-page foldout Slitherlink in Nikoli’s Puzzle the Giants 17 (essentially a grid of 30 8×8 small clued areas with a 2-square empty trough separating each), and a large Extra Kakuro on nikoli.com 3 or 4 years ago, which had a grid of islands only connected to each other via 9-square 45’s – gave it an interesting bit of Sudoku feel.

Fun low-difficulty flow to this one, making deductions about the tic-tac-toe grid to help settle the cell mini-games. I think I’ve worked out why it was necessary to shorten the top spoke of the lower-right grid T. Having become used to your aesthetics and level of detail, when I noticed it, my instinct was to wonder why you *couldn’t* connect the grid T’s, and not why you *didn’t*.. ðŸ˜‰

• MellowMelon Says:

It’s been awhile, but I’m pretty sure the reason for the incomplete T room was simple entrance exit counting, which came down to the fact that the four grid-line rooms have eight visits altogether but there are nine cells the loop has to go through. But yes, you know me quite well if you realized I would have gotten a puzzle with the full T shapes if it were at all possible.

If you’re going to mention island puzzles, nikoli.com’s Pick of the Puzzles had a medium Akari that did it as well. Also, do you count things like 200 under that concept? Personally I like that kind of realization more than just separate regions of a single type, since it’s less homogeneous.

95 used to be one of the toughest on here, but I remember finding it an incredibly smooth solve on my last revisiting of some old puzzles, so I guess my Double Back understanding has evolved since then. More recent things like the two Minefields are probably far more difficult as a result.