User blog comment:ArtismScrub/3D Sudoku idea/@comment-37584292-20190310004911

Woah, you've been gone for a while! Nice to see you again. :)

So, about your Sudoku variant, this does already exist if you Google it, but your particular variant would require a very simple user interface or else it would certainly be too messy for a human to work through neatly.

With that said, I think if someone can create it (and it is possible), someone can solve it. Perhaps the addition of an extra dimension would force the number of clues to be so many that instead of being difficult, 3-D sudoku might actually be easier than the 2-D version! I'm not saying this is so - I really don't know - but it's something to think about.