In general usage, symmetry most often refers to mirror or reflective symmetry; that is, a line (in 2-D) or plane (in 3-D) can be drawn through an object such that the two halves are mirror images of ...

If symmetry is a sign of splendor, then the newly discovered Red Square nebula is one of the most beautiful objects in the universe. Seen in the infrared, the nebula resembles a giant, glowing red box ...