# 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.

# Puzzle 177: Geradeweg [unequal lengths]

And here’s a Geradeweg with unequal lengths.

Rules Solve as a regular Geradeweg. In addition, any two straight segments which meet at a point must have different lengths.

# Puzzle 176: Country Road [unequal lengths]

Another loop type in the unequal lengths variation:

Rules Solve as a regular Country Road. Additionally, any two straight segments that meet at a point must have different lengths.

# Puzzle 175: Masyu [unequal lengths]

Continuing with the variant rule from the recent GP, here’s a Masyu [unequal lengths].

Rules Solve as a regular Masyu puzzle. In addition, any two straight line segments that meet at a corner must have different lengths.

# 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 161: Semitransparent Snake

Next one, a Semitransparent Snake. This was hardly worth constructing, since the competition puzzle was only worth 20 points. Also the type is somewhat dreadfully confusing. But, enjoy!

Rules Connect Start to Finish by a standard snake. Clues count the visible snake cells. Along any straight segment of snake cells (in the direction start to finish), every 4th cells is invisible (from both directions).

Or see the instruction booklet.

# Puzzle 159: Inner Coral

Next WPC preparation puzzle, this one from round 5, Variations. You might as well call it a First Seen No-Islands Tapa.

Inner coral

Rules Shade some empty cells to form a Coral, compare Puzzle 27. The clue cells count as empty cells for the coral and can not be shaded. They indicate the lengths of the first blocks seen in each of the up to four directions.

Or better see the instruction booklet.