Sudoku Variants Series (489) - Fibonacci lines
(Published on 16. October 2026, 06:00 by Richard)
For this Sudoku Variants Project I have planned to publish a unique Sudoku variant every week.
Fibonacci lines
Inspiration for this type comes from wafflefries. Solve online in Sudokupad.
I will see how long it takes before I am running out of ideas.
Apply classic sudoku rules.
The grid contains Fibonacci lines that must be read from left to right.
Starting from the third digit on such a line, each digit is the sum of the two previous digits. When this sum exceeds nine, the sum is written as two separate digits ON THE SAME ROW, each in its own cell, in the reading order. The first digit after this multi-digit sum, is then again derived by adding its two predecessors.
Example of a sequence: 5-2-7-9-16-7. This sequence cannot be placed on the line that starts in R6C2, since the 1 and the 6 are then not on the same row.
Solution code: Row 9
Comments
on 20. October 2026, 22:10 by Rollo
Das ist auch meine Erfahrung. Nach dem zweiten Rätsel von wafflefries flutschte es. Ich kann wirklich empfehlen die auszuprobieren.
That is my experience too. After the second puzzle from wafflefries it slipped. I can really recommend trying them out.
on 20. October 2026, 15:18 by wafflefries
I haven't attempted it yet (waiting for some of my students to try it with me!), but I was thinking about trying "fibonacci arrows" with a 2 digit bulb (to designate the non-affected digits) and a direction (so the lines are no longer limited to just reading order).
Also, the break in, generally speaking, is pretty difficult. Once you "get" the puzzle, it becomes significantly easier to solve. 4* means you have a lot of first time solvers of the format. I would think that those who are already familiar with the format would rate it a 2-3*.
on 20. October 2026, 04:54 by Richard
I am a bit surprised that this one has four stars for difficulty. Players give me feedback that they needed to guess. That is not necessary, although it might be helpful to make a few small tables with (limited numbers of) possibilities for some of the lines. To solve the five puzzles from wafflefries, I made a long table with all possibile starting combinations. After three of his puzzles, I didn't need that table anymore, since I had a click with the logic.
It also might help that I still solve puzzles with pencil and paper; it's easier to make notes.
Anyhow. I have written the way to start this puzzle in a hidden comment, in case you guessed your way through the puzzle. Which would be a pity...
on 17. October 2026, 21:57 by da-hans
Very nice puzzle. Found no way to finish it without breaking a line until this one wrong digit left its place.
on 16. October 2026, 18:59 by Richard
Changed the link to the userpage of wafflefries.
on 16. October 2026, 16:41 by Franjo
Thank you very much for creating and sharing another great SVS-puzzle. This. Was. Not. Easy.
on 16. October 2026, 12:30 by Qodec
Very nice!
on 16. October 2026, 09:32 by Piatato
Cool!
on 16. October 2026, 08:22 by marcmees
Very nice. Thanks
on 16. October 2026, 08:15 by ibag
Sorry, I overlooked this sentence. ;-/
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Reply: no worries Gabi. I overlooked it while copying the text too. And it was fixed before it could lead to much confusion. :-)
on 16. October 2026, 07:32 by Richard
Added missing German sentence. Thx Realshaggy!
on 16. October 2026, 07:29 by Realshaggy
"Das Gitter enthält Fibonacci-Linien, die von links nach rechts gelesen werden müssen. Jede Ziffer ist die Summe von den beiden vorangegangenen Ziffern."
on 16. October 2026, 07:16 by Realshaggy
The german instructions are missing the part where it says, that the line has to be read left to right.
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I didn't notice that. Can you write the German sentence?
on 16. October 2026, 07:14 by Realshaggy
Is there a reason to use such an annoying link shortener for wafflefries Fibonacci puzzles, that redirects to the puzzle portal anyway? It takes ages pretending it is doing some "checks". (Probably it just lets you wait on purpose to show you the advertisement.)
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Without a tinyurl the link doesn't work. I am not aware of another way to do this.
