# 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 125: Skyscrapers Domino Construction

Edit I’ve since convinced myself there’s a reasonable way through. Still really hard, but no longer a puzzle I feel bad about.

Rules Place the given set of dominoes in the marked domino tiles. Whenever two dominoes touch by an edge, the adjacent numbers must be the same. Clues outside the grid are skyscraper clues: They indicate the number of visible skyscrapers when looking along the corresponding row or column from that point, where each number represents a skyscraper of that height. Skyscrapers are blocked from view by those of greater or equal height.

Or see the instruction booklet.

# Puzzle 124: Skyscrapers Domino Construction

Is it just me, or are there more uncommon types on this round than previously? Anyway, below there’s a Skyscrapers Domino Construction. Again these were on the 24 hours this year. This one is probably not typical, but I think it came out quite well.

Rules Place the given set of dominoes in the marked domino tiles. Whenever two dominoes touch by an edge, the adjacent numbers must be the same. Clues outside the grid are skyscraper clues: They indicate the number of visible skyscrapers when looking along the corresponding row or column from that point, where each number represents a skyscraper of that height. Skyscrapers are blocked from view by those of greater or equal height.

Or see the instruction booklet.

# Puzzle 123: Countries

Countries is another type from the Russian GP that I first saw in Budapest this year. This one should show that some of the deductions that seem almost correct aren’t always.

You might want to resolve it with full clues to get something more like the GP puzzles, though I suspect that that bypasses quite a bit of the logic.

Edit Fixed an ambiguity (second try), thanks Neil!

Rules Subdivide the grid into orthogonally connected areas (“countries”), each containing exactly one letter. Numbers outside the grid give the number of cells in that row or column that are part of the first country in that row or column.

Or see the instruction booklet.

# Puzzle 122: Paint By Threes

Continuing with the GP practice puzzles, here’s a Paint By Threes. I believe I’ve seen these more than once at the 24 hours, see Puzzle 121 for a link to the 2016 puzzles. There were a few on croco, too: Dreier-Nonogramm 1, Dreier-Nonogramm 2Dreier-Nonogramm 3. I tried to make this one a bit harder.

Rules Replace each circle with a non-zero number, divisible by three if and only if the circle is black. Then solve as a standard nonogram. I.e., shade some cells, such that the clues give the sizes of all blocks of shaded cells within that row or column, in the correct order.

Or see the instruction booklet. (In the competition presentation, white/black circles are replaced by white/gray squares.)

# 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 66: Japanese Sums with 0

Long time no post. I’ve been making puzzles for croco-puzzle recently, the ongoing Best of 24h series, in particular.

But, here’s a practice puzzle for the coming German GP round next weekend. It’s on the hard side — I’d be interested to hear if you find (a way around) the intended break-in.

Rules Shade some cells, and fill the remaining cells with digits from 0 to 6, such that no digit occurs more than once in each row or column. The numbers outside the grid indicate the sums of blocks of connected digits in the correct order. This includes single digits.

Example (digits 0-3)