Today's grid has left-right mirror symmetry. That is, it is symmetrical around a vertical line down the center of the puzzle. Mirror symmetry often results in some interesting grid patterns.

I LOVE symmetry photography in my portrait, landscape and architectural work. Is it better than the rule of thirds?

The line is called a line of symmetry. This is sometimes called a 'mirror line' or 'mirror symmetry', because if you put a mirror on the line, the reflection would show the whole shape.

This bold concept could address dark matter mysteries and explain cosmic symmetry gaps. In Turok’s hypothesis, right-handed neutrinos—unobserved in our universe—could exist in the mirror ...

N-Rotation Point (a point with C_N symmetry) - indicated by the number N before any * Mirror Symmetry (a reflection) - indicated by a * M-Dihedral Symmetry Point (a point with D_M symmetry) - ...

The line is called a line of symmetry. This is sometimes called a 'mirror line' or 'mirror symmetry', because if you put a mirror on the line, the reflection would show the whole shape.