Logic Masters Deutschland e.V.

To Christmas 2016 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.

Oddus and Evenus

Santa Claus had a problem: His puzzle present order for a dear puzzle mate had gone lost somewhere on its mail way and now laid probably unnoticed somewhere around the north pole in a store. What now? He went to his puzzle gnomes Oddus and Evenus and told them about his mishap. "Don't you have any nice puzzle left? You know, how much she likes to fiddle about with puzzles." he asked the two bluntly.

"You're lucky", said Oddus, "oddly enough we just have tried something. Take a look." and he showed Santa Claus a sheet with a grid on it. "We started with a complete filled standard Sudoku. Then we blackened in each row, column and marked area two cells. No two black cells share an edge." " All right", said Santa Claus a bit puzzled, "and what next?". "Well", added Evenus, "the rest is simple: At the top above the even columns I wrote the sums of numbers in the blocks built by black cells and diagram borders and Oddus did the same for the odd rows." "And what about the letters at the left?" asked Santa Claus. "Right, they show, if the sum of numbers in not blackened cells in the row is odd or even. Every one of us wrote one letter. Guess who did which." Oddus answered grinning. "And of course finally we removed the numbers and colours. It should be a puzzle, right?" Evenus completed.

"That's enough. Small, but nice! Thank you very much!", said Santa claus gladly and send the puzzle on its journey.