Like a butterfly, the human body has bilateral symmetry. That is, the right side of the body and the left side are mirror images of each other.
Dance training exploits bilateral symmetry. If a sequence is performed leading with the right side of the body, it is also practiced leading with the left.
Bilateral symmetry wasn’t enough for Rudolf Laban. He thought dancers should train for symmetry in all three dimensions. He designed movement scales for just this purpose.
Find out more in “His Hand and Head: How Laban Created Movement Patterns.”