All good works of art must be unified - all the elements must work together as one. That is not to say that everything must be symmetrical.
Some visual elements carry more weight than others.
Sculptures must achieve balance or else they would fall over. Alberto Giacometti was influenced by Egyptian sculpture. It is an all-over composition. The various bodies are pushing and pulling, leaning this way and that in a great struggle. Go to your textbook on pages 88 and 89.