Since it is a (caution: MAJOR) hint, the answer to your question is in the spoiler:

As a sidenote, sometimes (not sure if

**Spoiler**

*:*

these types of puzzles most typically involve common sets or variations and can either have continuity in a row or in a diagonal, or both but each for different elements, and there are two types of diagonals (and so-called 'broken diagonals').

As a sidenote, sometimes (not sure if

*always*- haven't restudied matrices currently) the pattern can be mathematically expressed very briefly.
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