Kaodokus are a new variation of sudoku with symbols that are only partially given. Originally invented for Belgian Mensa magazine Commensal, kaodokus offer a lot more variety than ordinary sudokus.
Instead of numbers, the cells contain smiley faces which can have three possible shapes and three possible mouths. Each of the nine unique combinations has to appear exactly once in each column, row or other marked area just like in a normal sudoku.
The big novelty is that in some cells only the mouth or shape is given, leaving the missing part for you to find. You can even ask for grids that initially don't include a single full symbol! This makes the puzzle experience a lot richer, requiring complex strategies combining bits and pieces of information in original ways.
Kaodoku is a free download from the Apple app store.
For more information, bug reports, questions or support, read the frequently asked questions or contact the author at: