# Puzzle 130: Divisor Sudoku

Here’s a Divisor Sudoku. I made this one for the 24h review series on croco earlier this year, but ended up making a second easier one. Please excuse the lazy rendering.

Rules Standard Sudoku rules. In addition, the givens indicate a divisor of the corresponding two-digit number (left-right or up-down).

# Puzzle 129: Skyscrapers (with parks)

A companion skyscrapers puzzle to puzzle 119. This was the first one I made, 119 was meant to be easier, but still too hard.

Buildings of size 1-9 and one park (gap, invisible) per row and column.

EDIT fixed shifted clues along the top.

# Puzzle 128: Pentomino pipes

Here’s something new, a puzzle I made when a friend asked for “something with pipes”. I think the general idea of finding a pentomino net works quite well, though I’m not convinced of the details of the mechanics in this version. In particular, some other kind of clues might work better, e.g., giving the connection dots.

Edit Amended the rules to hack the puzzle to uniqueness.

Rules Place a full set of pentominoes onto the grid lines. (Each pentomino cell maps to a vertex, and adjacent vertices are connected by an edge, like the clues from Puzzle 82.) Each edge may be part of at most one pentomino. If two pentominoes touch at a vertex, there must be exactly two pentomino edges touching that vertex. There must not be any vertices with a single edge.

Wherever a vertex is marked by a letter, that vertex must be one of the five vertices of the pentomino corresponding to that letter. There may be still be a second pentomino using that vertex.

Pentominoes may be rotated and mirrored. Except F: F may be rotated but must be oriented as in the example solution.

Example with pentominos F, U, V, Y.

# Puzzle 127: Summon

Have a Summon. If you’ve already figured out the kind of argument this one is built around it’s not that difficult.

# 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.