so true if im mathematician, i would definitely explain how by using math.

but idk its something built into my head, my brain so yeah.

this is just as quickly as im typing here: 3x3

4 9 2
3 5 7
8 1 6

sum 15, horizontally and vertically and diagonally.
of course this is for total sum must be the same.
i built a check-sum algro based on this.

anyhow, as for sorting in unique order i can do that as well, for example the word ASM.
and im not limited to 3x3 grid, i can go up to 10.

This is often the way things progress. For example, the general MxN algorithm producing minimal clues: I feel I could construct a program to build these puzzles, but don't know enough mathematics to prove the general case - intuitively it seems as if it must be true. I've searched for a paper of similar and nothing. Maybe it is out there in Chinese or Russian. The tools used in such a proof would be useful elsewhere.

It is like in programming when we talk about algorithms - they are base examples of a technique and can be pieced together like Legos, or used in spirit as our comfort with them increases. There are some great write-ups in programming describing high-level algorithms where the genius and novelty is quite inspiring.