If you found that video interesting, then perhaps this is an interesting picture. [Someone going by the pseudonym shye is responsible for this puzzle, and it even has a name. Imagine that, dearest reader: a sudoku with a name! Rather grandly, this one is called "Valtari"]
If you found that picture interesting, then perhaps these are some interesting words.
- Add rows 1, 3, 5, 7, 9 together with box 5 (in blue, with double weights in R5C4 and R5C6).
- Subtract Columns 3, 5, 7 (in red).
- The blue cells, considered with multiplicity, have the same contents as the red cells plus 3 extra copies of the digits 1-9.
- In the double-weighted blue cells, the only possibilities are 2, 3 and 4.
- There are already exactly two each of 2, 3 and 4 appearing as given digits in the single-weighted blue cells.
- This means that whichever two of the three digits ends up in the double-weighted blue cells will end up bring the multiplicity of both of those digits up to 4 within the blue cells.
- This means that the two empty red cells have the same contents as the two empty double-weighted blue cells.
- It also means that those two digits cannot appear again in any other blue cell.
- More on this to come I'm sure, following this good work by Philip Newman: https://docs.google.com/document/d/1Y7m2tTUDmUTj3BZ0w5viNuQlaiBVv9kmYksSLrm_XLE/edit
UPDATE: as far as I can tell, there is no need to add Box 5 to the equation here - this makes the intersections slightly simpler (no need for double-weights any more) - but it does make it harder to identify where you are supposed to be looking.
If you didn't find that interesting, then I'll leave you with some whimsical musings. I always thought that an obscure and difficult sudoku solving technique going by the name Exocet was named for a powerful missile that could bust open the hardest of puzzles. Cela a plus de sens en français.