This is the first one:

- Code: Select all
`.. 18 18 03`

.. 15 18 18

15 15 18 18

15 15 15 15

06 06 indicates a 2-cell cage totaling 6.

I have not found a 4x4 Killer Su-Doku harder than this. Please let me know if you have.

This is the second one:

- Code: Select all
`16 16 16 16`

.. 16 16 16

------

16 16 16 ..

16 .. 16 ..

The dashes show the dividing line between the two cages. There are only two cages in this puzzle, and I think that this is the minimum. It is also the only puzzle that I have found where every cage adds up to the same number.

What do you think of my puzzles?