Normal sudoku rules apply.
All cells are either a zombie or a human. No 2x2 area of cells are just zombies or just humans.
If a cell is orthogonally connected to a zombie cell with a higher digit it becomes infected and becomes a zombie.
If a cell with a 9 is orthogonally connected to a zombie cell with a 1 it becomes infected and becomes a zombie.
The cell with the circle is patient zero. It is a zombie. The infections of all the other zombies can be traced back to patient zero.
No other cells are zombie cells.
The puzzle:
Many thanks to Greg Morenz for making a computer program that found a valid grid.
Solve on f-puzzles: Link
Solve on Cracking the Cryptic app: Link
Solution code: Row 1, left to right, no gaps between numbers.
on 25. August 2023, 02:57 by damasosos92
Astonishing. Added to my favourites!
on 19. December 2022, 10:58 by MagnusJosefsson
Great puzzle, original and enjoyable!
on 13. December 2022, 17:10 by Christounet
Beautiful ! I wonder how you managed to have such a nice solution path with a computer-generated grid ? Or maybe it just helped you to polish things and avoid broken grids when you had the basic ideas laid out ?
Anyway, I had a great time sorting out the victims of that zombidemy. Thanks.
[Thorsby: No, the grid is completely computer generated. Only the cell of patient zero was decided. I got lucky it turned out so well.]
on 12. December 2022, 18:35 by kjholt
Once I got the hang of it this was very smooth but tougher than it looks! I really liked it; such a creative twist!
on 12. December 2022, 16:05 by 10feet
What an innovative idea! It was really fun, thanks.
on 11. December 2022, 16:54 by PrimeWeasel
Really cool and creative construction!
on 11. December 2022, 08:40 by plica
Really nice puzzle!