Symmetry
Balance produced by exact mirrored correspondence across a central axis.
In practice
Symmetry arranges elements as exact mirror images on either side of an axis, usually vertical. It reads as stable, formal and ordered, and it is the most straightforward way to achieve balance. A centered wedding invitation, a classical building facade and a logo shaped like a butterfly all rely on it. Designers sometimes break strict symmetry slightly so that the result feels less rigid while staying calm.
Often confused with Balance
Symmetry is mirrored sameness across an axis; balance is any stable distribution of visual weight, which symmetry is only one way to reach.
Try this
Fold a sheet of paper, cut a shape along the fold, and open it to see mirror symmetry appear.