Symmetry in biology is the balanced distribution of duplicate body parts or shapes. In nature and biology, symmetry is approximate. For example, plant leaves, while considered symmetric, rarely match up exactly when folded in half. Symmetry creates a class of patterns in nature, where the near-repetition of the pattern element is by reflection or rotation. The body plans of most multicellular organisms exhibit some form of symmetry, whether radial symmetry, bilateral symmetry or "spherical symmetry". A small minority, notably the sponges, exhibit no symmetry (are asymmetric).