That’s a neat observation—if you cut a square along a line through its center, each half is a rectangle, and by rotating one you get two congruent squares. It’s a simple illustration of symmetry and how a single shape can be divided yet remain balanced.

When you cut a square in half, each piece keeps the same proportions as the whole, so in that sense they’re both reflections of each other. But the two halves only reconstruct the original when they’re put back together; the whole can’t be contained by one half. It’s like a puzzle—each piece is a part of the picture, but the picture itself is larger than any single piece.