Four By Four
(Published on 29. February 2024, 17:13 by IcyFruit)
Normal sudoku rules apply.
Shade some tetrominoes (groups of 4 orthogonally connected cells) such that no two tetrominoes are orthogonally or diagonally adjacent, all unshaded cells form a single orthogonally connected region, and no 2x2 square of cells is entirely unshaded.
Clues in a circle indicate the values of all shaded digits in the 4 cells surrounding the clue. Each question mark represents a single digit, which must be unique within that circle.
Adjacent unshaded digits differ by at least 4.
Solution code: Columns 4 and 9
Comments
on 10. August 2024, 03:39 by Silverstep
This is very easy and not interesting. Not sure why a lot of people liked it so much.
on 11. March 2024, 00:27 by yttrio
Very fun puzzle! Both the shaded cell and unshaded cell logic required were great!
on 3. March 2024, 13:53 by henrypijames
The rules state that every question mark represent a single unique digit, but don't say if non-question-marks do the same. For instance, may the single 5 in a circle represent two different shaded 5s in that quad?
Suggested rephrasing:
Within every circle, each digit (including ones represented as ?) is unique and corresponds to a single shaded cell touched by the circle.
on 1. March 2024, 13:20 by samuel1997
Absolutely brilliant!
I somehow brook the puzzle though by misunderstanding the rule that I thought the digit in circle must be shaded and must be the only digit surround the circle. But after that the puzzle went on well.
on 1. March 2024, 09:52 by Playmaker6174
A fascinating rule set that provides some cool yet unusual sudoku deductions.
Wouldn’t really say it’s so smooth overall because there’re couples of points in the middle where I had to ask proper questions about the unshaded cells, but it was still pleasant to solve till the end :)
on 29. February 2024, 19:00 by glum_hippo
Very enjoyable, and inspiring too
on 29. February 2024, 18:22 by goodcity
Loved the puzzle and the ruleset ! The solve felt so smooth, I am not sure about the stated difficulty. Anyway thank you for setting and sharing :)
