3. Primes as “DIAGONAL Sums”

Sums are diagonal or have a diagonal visual effect, when visualised in “Functional Matrices”:

ODD Vertical Digits are added to ODD Horizontal Digits on the LEFT and to EVEN Horizontal Digits on the RIGHT. The Results are EVEN Diagonals Left and ODD Diagonals Right.

When adding EVEN Horizontal Digits to EVEN Vertical Digits, again, the result are EVEN Diagonals.
The Diagonals are ODD when ODD Digits are added to EVEN.

But the Geometry of Diagonals is more important than the Arithmetic of Odd or Even!

When ANY sum can be visualised as a Diagonal, so can Prime Numbers of course: