4×4×4
(Published on 16. January 2026, 00:31 by juggler)
In each quadrant, normal 4x4 Sudoku rules apply, i.e. place the digits 1-4 once each in every row, column, and box.
Red shapes always sum to one of four possible sums, and these four sums appear once each in every row, column, and box of the large 4x4 Sudoku.
(Example)
Solution code: Row 1 (8 digits)
Comments
today, 04:19 by ScatterBrain
It's a great idea. Hard to explain, but once you understand it, it's fun!
Thanks.
yesterday, 19:27 by juggler
(Example image)
yesterday, 19:09 by jez9999
Yeah, I don't understand the rules on this either. Does "box of the large 4x4 Sudoku" mean a small box (which is redundant) or a quadrant? Also, does "appearing in the same row" count as any digit of a box appearing in the same row/column, or do all the digits of the two boxes have to be in the same row/column to violate the rule?
Update: OK... figured it out anyway. The larger sudoku's four unique cell values are that of the red boxes.
yesterday, 11:46 by GandalfLeRouge
Very cool puzzle! I give it two stars though because the rule set is a little complicated to understand, with the quadrant and everything (though it might be because i'm not a native english speaker)
Thanks juggler!
on 19. January 2026, 21:38 by Snaques
I'd love to give this a go, but the rules are too confusing and I don't want to start guessing.
Is a "large 4x4 Sudoku" just one quadrant?
Is "box" one 2x2 region within a quadrant?
I assume they can repeat in the entire grid as there are only four distinct values.
---
juggler: each 2x2 box of a small 4x4 grid acts as a "cell" for the large 4x4 grid. The value of that cell is the sum of its red shape. I've added an example image.
on 17. January 2026, 18:58 by chubnatty
Lovely breakin, and such a dopamine hit when I finally saw the last step that unraveled everything.
on 17. January 2026, 12:02 by TeddieMilo
Very interesting.. but it took me a while to understand the rules with some experiments.. very nice, tq.
on 16. January 2026, 22:36 by firespire
Very interesting.
on 16. January 2026, 18:40 by blackjackfitz
Huzzah!
on 16. January 2026, 17:14 by HeyItsErin
Trickier than I expected but very fun!
on 16. January 2026, 01:42 by dzamie
Surprisingly nontrivial, and a lot of fun!
on 16. January 2026, 01:26 by Atticus837
What a lovely idea! Not difficult, but very enjoyable to think through.
