Yin-Yang: Divide the grid into fields with white and black circles. Both black and white circles form an orthogonally connected area, which must not contain any 2x2 area.
Every cell has to be filled with a circle, except those marked with an X, which must be left empty.
Some circles are already given.
Solution code: for each row the number of black circles
on 1. April 2026, 22:48 by stinger10x
online solving
https://sudokupad.app/7zwsxe4qxo
on 1. November 2013, 16:56 by SilBer
Was hab ich übersehen - wieso ist das typisch??
on 31. October 2013, 10:15 by ibag
... und der ist ja beinahe noch typischer. ;-)) So macht Halloween Spass!