Logic Masters Deutschland e.V.

To Christmas 2023 some eager puzzlefriends have again arranged a group in which everybody had to make anonymously a puzzle for someone else. These puzzles are now presented one after the other here in the portal.

A few nights before Christmas, all the Christmas elves made their final preparations for the big day. Sets of orthogonally connected gift boxes were packaged in festive wrapping paper, ribbons were tied into loops, which never crossed the same cell twice, and the whole workshop was buzzing with joy. On the top floor, however, three gnomes had assembled with a difficult problem for Santa Claus. Wave, Wapa, and Wurikabe were standing around their completed puzzle... or at least... their completed grid. They had drawn a pretty shading pattern in the grid which was orthogonally connected and left no 2x2 area fully shaded. But the dwarves had different ideas about how to festoon the puzzle with clues.

„Anyone who looks at the grid long enough can tell precisely what it needs“, argued Wave, and notated the clues that he would add to the grid. „Clues are not shaded, and indicate the total number of unshaded cells that can be seen from that vantage point in all orthogonal directions.“ But before she could finish writing in all the clues, another elf had snatched the pen from her hand.

„Then you clearly haven't looked at the puzzle long enough, for anyone with eyes in their head can see that it's already a standard puzzle genre. Look. The clues are all unshaded, and indicate the lengths of the shaded cell blocks in the neighboring cells. If a cell contains a Tapa-clue, then of course they all must be...“ Wapa got to work, and added his own clues to some of the cells, even to some that already contained Wave's clues, just to infuriate her.

„Yes, indeed it's a standard puzzle genre, but who in their right mind would look at this grid and think of Tapa?“ Wurikabe pushed Wapa aside and marked a single clue into each orthogonally connected unshaded region. „No, obviously this grid needs exactly one clue per island, whereby each gives the count of cells in that island.“ When each island finally had one of its clues, the grid was indeed impenetrably complex. Clues from all three gnomes were sometimes crowded into a single cell, and in the madness some digits were even utterly illegible.

During all this chaos, Santa Claus desperately tried to analyse a map of the subterranean north pole train network, on which for some reason four different kinds of information had been encoded. Since so many important gifts had gotten lost in the tunnels, he had no time for these kinds of conflicts. All three dwarves had had perfectly good ideas, and each of them, taken alone, would have resulted in a nice puzzle. „Very well,“ the large man finally arose. „Go on, wrap it all up and send it out. I have some freight shipments to attend to.“ And with a twinkle of the eye and a twist of his cap Santa had vanished and left the dwarves behind, befuddled.

„Did you hear him say this looks all right?“ Wave looked upon the chaos that they had produced. „Well, I mean, we're the ones who put it together, and all, but... did he even look at the puzzle itself?“ Wapa asked, looking over at Wurikabe, who placed a reassuring hand on Wapa's shoulder. „Remember, Santa is magical. Who's to say that he isn't able to logically deduce everything in the blink of an eye? If the great man says that it's a puzzle, then it must be one.“ All three smiled, as they began to carry their creation into the packaging room. One lucky individual was going to be receiving a very interesting puzzle this year...