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.

The gnomes Mia und Max are once again tiptoeing to and fro in the gnome workshop, in hopes of swiping ingredients for their new puzzle. They just raided the gnome bakery and are now assessing their loot.
„I have pilfered two complete sets of freshly baked pentomino cookies,“ Mia gleefully reports, „and they fit perfectly into the grid that we filched over in the carpenter’s workshop. A few dividing lines were already inlaid there, which was really practical.“
„Awesome, and I stole a frosting nozzle, a bag of almonds, as well as some chocolate glaze. We could either coat each pentomino area in chocolate, decorate it with an almond, or squirt a number from 0 to 9 on it“ Max replies. „Of course, all the digits on a pentomino must be different.“
„Then let’s use the pentominoes to lay out a Japanese Sums puzzle in the grid. Each row and column must contain no repeat digits. The chocolate cells are the blackened cells of the puzzle. The almonds act as minus signs, so we can also include negative numbers. An uninterrupted stretch of digits (with or without a preceding almond) on a pentomino forms a number, so we can also have numbers greater than 9 or less than -9. A number is complete when either the pentomino ends, or a blackened cell appears, or a minus sign appears, which would also mean the next number is a negative one.“ Mia suggests.
„I don’t understand“, says Max, who always needs things explained very precisely. „Doesn’t that mean you could get numbers starting with zero, or isolated negative signs, or even the number -0?“ „No“, says Mia, „that sort of thing is of course not allowed. The numbers all look totally normal. But the number 0 is certainly possible.“
„So then Oxym will get the whole grid, with all those beautiful cookies, as a gift?“ Max asks with alarm. „Don’t worry“,Mia responds, „let’s just calculate the sums, encode them, and write them along the edges. Then we can just eat the cookies, and give the grid to Oxym. He’ll be able to find out where the cookies used to be, and what was in the individual cells.“