Author Archives: rob

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

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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 2, Dreier-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

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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 120: Hochhausblöcke

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Some more Hochhausblöcke. In other news, the 10×10×10 series on croco-puzzle continues, and I submitted a few puzzles to the excellent puzzlepicnic, including a Fences puzzle where I’m curious to know if people find the intended break-in, and a Yajilin.

Rules Place numbers from 1 to 4 in each cell so that each row and column of each 4×4-block contains all numbers 1 to 4. Circled numbers are valid skyscraper clues for the adjacent grid (for both adjacent grids in the central corners). Uncircled numbers are not valid skyscraper clues for the adjacent grid (for neither adjacent grid in the central corners).

Puzzle 119: Skyscrapers (with parks)

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Here’s a skyscrapers puzzle. This is from a batch of puzzles I recently made for a series on croco-puzzle, consisting of 10 puzzles on 10×10 grids. I thought it was a nice opportunity to try my hands at making a large skyscraper puzzle, after some failed attempts in the past. The difficulty turned out such that it didn’t really fit with the rest of the series, so here you go.

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