Monthly Archives: March 2014

Puzzle set: 24 Hour Puzzle Marathon

I contributed one round of puzzles to this year’s 24 hour puzzle marathon in Budapest. Solvers had 100 minutes time, with a target of roughly 800 out of 1000 points for the best solvers. You can download the full booklet, or go through them individually (with a bit of commentary) below.

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Puzzle 19: Count Numbers (Meandering Numbers)


One more GP practice puzzle.

Rules Place a number in each cell. The numbers within an area go from 1 to the size of that area, with consecutive numbers horizontally or vertically adjacent. Cells with equal numbers (necessarily from different areas) must not touch, not even diagonally.

Or see the instruction booklet.

Puzzle 18: Afternoon Skyscrapers




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

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


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

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.