Author Archives: rob

Puzzle 22: Japanese Sums and Loop

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The Czech round of the puzzle GP will take place next week, the instruction booklet has been posted. Here’s a practice puzzle for one of the types.
japsum-loop

 

Rules Place numbers from 1 to 6 in some cells so that no number repeats within a row or column. For rows and columns that have clues given on the outside, these numbers correspond to all sums of blocks of adjacent digits within that line, in the correct order. Furthermore, draw a loop that visits all cells without a number, passing horizontally and vertically from cell centre to cell centre.

Drawing puzzles with the Haskell Diagrams framework

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A while ago I alluded to some puzzle rendering project I was working on, today I want to give a small update. It’s a Haskell library called puzzle-draw, the source code is available on github. It’s  in a state where it’s useful to me (I used it for the entire marathon set, for instance), not necessarily quite ready for public consumption.

If you just want to play around with it, I’ve hacked together a web demo, below I’ll give an overview and explain how to install the command line tool.

EDIT: The command line tool has since changed to not require cairo by default, see the comments.
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Puzzle 21: Inversed LITS

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litsinverse

 

Bram made one of these for the 24 hour puzzle marathon, see his set. This puzzle probably explains why the marathon one was only solved by Germans…

 

Rules Shade some cells to form an orthogonally connected wall that contains no 2×2 square. The white cells within an area must form a tetromino, and two tetrominos that share an edge must not be of the same type. (The O-tetromino is possible.)

Puzzle 18: Afternoon Skyscrapers

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afternoonskyscrapers

 

Another practice puzzle for the GP.

Rules Fill the grid with numbers from 1 to 6 such that every row and column contains all numbers. The numbers represent skyscrapers of the given height. There is a gray shadow at the south edge of a cell if some skyscraper further south in that column would throw a shadow onto the roof of the skyscraper in that cell, with the sun shining at a 45º angle. Similarly, a shadow on the west edge corresponds to sunshine from the west.

Or see the instruction booklet.

Puzzle 17: Box of 2 or 3

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Here’s a small practice puzzle for one of the new (to me) types at next weekend’s Japanese round of the puzzle GP.

boxof2or3

Rules Group some circles into boxes, such that each box contains two or three circles, such that all circles within a box are connected by edges within that box, and such that edges don’t connect circles that belong to different boxes of the same size. Furthermore, all black circles must be boxed.

Puzzle 16: Compass

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Just survived this year’s 24h puzzle championship in Budapest! Congrats to the winners (Peter Hudak in first, edging out Nikola Zivanovic and Zoltan Horvath), and to Nils for winning the fight for best German. I expect to post (or link to) my contribution at some point, but for now here’s a Compass puzzle that I skipped in favour of two more accessible ones. Inspired by Nikolai’s survey of almost symmetric puzzles.

compass-symm