# Puzzle 203: Slitherlink [just one segment]

It’s always fun to figure out some new arguments in a puzzle type. While going through @taburega’s tough puzzles, I ran into one occurrence of a pattern I didn’t know before, and recently managed to distill it into something a bit more memorable while finding some similar arguments in a kwontomloop.com puzzle.

I’m curious how well known these techniques are, let me know! I hope to follow this up with a discussion of the “theory” at some point.

Rules This is a Slitherlink puzzles with many solutions, all of which share one segment. Find that segment.

# Puzzles 186-188: Standard / Touching Slitherlink

Here are a couple of puzzles of widely varying difficulty that I made for the hybrid type Standard / Touching Slitherlink that featured in Round 8 (Twilight) of WPC 2019. I could have sworn this variant existed somewhere on the Rätselportal or in the Logic Masters archives, but I couldn’t find it. It’s quite similar in some ways to related hybrids like “Außen-Knapp-daneben-Rundweg”, but has some quite novel features.

Edit Added a clue to the 3s-puzzle to save the intended break-in.

Rules Draw a loop by connecting grid points as in standard Slitherlink. Clues inside the loop act as standard Slitherlink clues (i.e., they count adjacent edges that are used by the loop). Clues outside the loop count how often the loop visits the boundary of the cell, as in Berührungsrundweg (e.g., a clue 4 means that the loop uses all of the cells corners but none of the sides).
Or see the instruction booklet.

Here’s a Slither Link puzzle with a restrictive theme, that I found with computer assistance, after failing for a while at constructing one by hand. The idea is due to @RainedMirror from the Puzzler’s Club discord. (If you’re interested in puzzle discussions, check the LMI thread for the recent contest for information on how to join.)

# Puzzle 174: Slitherlink (Unequal Lengths), and Russian GP recap

This past weekend, the WPF hosted round 4 of the 2019 Puzzle Grand Prix, with puzzles by Russian authors. Puzzles/solutions/results are currently available under the previous link but should show up in the archive eventually. I’ll go over how it went for me below. One very interesting new variant on the test was “unequal lengths slitherlink”; here’s one:

Rules Solve as a regular slitherlink. In addition, any two connected straight line segments must have different lengths.

# Puzzle 126: Yin-Yang Fences

And quickly another post to hide that terrible Domino Construction. In contrast, this one has a nice solving path, but will you find it?

Rules Solve as a standard Slither Link. In addition, all cells outside the loop must be connected, and there must be no 2×2-square of cells that is entirely inside or outside the loop.

Or see the instruction booklet.

# Puzzle 121: Yin-Yang Fences

The next GP round is coming up, with the Russian GP authored by Andrey Bogdanov. One of the types is Yin-Yang Fences, which I first saw on Andrey and Vladimir’s round for the Budapest 24 hours this year. You should be able to find these here. Berni made another for our croco 24h review series.

You can leave out one of the 2s on the outside if you want more of a challenge.

Rules Solve as a standard Slither Link. In addition, all cells outside the loop must be connected, and there must be no 2×2-square of cells that is entirely inside or outside the loop.

Or see the instruction booklet.

# Puzzle 103: Keller, Fences+Dominoes

Next Keller puzzle. Some of the logic may have been lost in completing the domino part for this one. I find the restrictions that the compatible domino tiling imposes on the loop to be quite interesting in this type, the interaction with the domino puzzle as such less so.

Rules The left grid is a domino dissection puzzle. Divide the grid into 2×1-areas such that each domino occurs exactly once. The right grid is a standard fences/slitherlink.

The grids interact: Superimposed over the solved domino grid, the fence can’t bisect a domino.

# Puzzle 96: Ecken- und Kantenrundweg

As a bit of a breather before posting more JaTaHoKus, here’s a puzzle for one of the new types, at least I hadn’t seen it before. It was on the mixed round of the Logic Masters. It’s an “edge and corner fences”.

Rules Draw a single loop consisting of vertical and horizontal segments between dots that does not touch or cross itself. Clue numbers indicate the number of adjacent edges and corners that are used by the loop.