Shapes conjure up feelings and inform both abstract and specific states of consciousness. For example, circles appear in many cultures with an archetypal symbolism of oneness. They are round and endless, seamless, infinite, and whole... an expression of perfection, of equality in all directions. For subtle reasons, circles represent the feminine... they also represent unity and eternity.
The Ouroboros, a snake or dragon forming a circle with its tail in its mouth continually devouring itself and being reborn from itself, is a symbol of eternity and of the cyclic nature of the universe. It expresses the unity of all things, which never disappear but change form in a cycle of destruction and re-creation.
In Zen Buddhism, the circle represents the entire universe in a single, perfect stroke.
The Wheel of the Year is a Neopagan and Wiccan symbol for the Earth's cyclical seasons. Buddhism's eight spoked wheel, the Dharmachakra, represents the teachings of the Buddha and the cycle of birth and rebirth.
The square is a symbol of mathematical perfection... it depicts the four earthly elements, the four cardinal directions of physical space and time. It represents concrete reality, stability, and logic. Squares are sound, sturdy, pragmatic, and full of right angles. They represent building blocks, integrity, and dependability.
Triangles represent balance, equanimity, harmony, enlightenment, Ascension, the Holy Trinity, the Triple Goddess, and the three realms of sleeping, dreaming, and dying... of underworld, this world, and the heavens... past, present, future... mother, father, child... love, truth, wisdom... maiden, mother, crone... creator, destroyer, sustainer.
Hearts are love...
Stars are the goddess... but it's not just geometric shapes that conjure up archetypes. The word, "swastika" comes from the Sanskrit, svástika, and and dates from the Neolithic period as a religious symbol. "Once commonly used all over much of the world without stigma, because of its iconic usage in Nazi Germany the symbol has become stigmatized in the Western world, notably even outlawed in Germany."(http://en.wikipedia.org/wiki/Swastika).
One might argue that this tells us symbols hold inherent meaning AND can evolve to take on drastically different socio-political meanings.
Think about this...
The Goddess of Willendorf...
With an estimated origin at 30,000 - 25,000 BCE, she's quite possibly the earliest depiction of the human form and "the first known religious image of the Mother Goddess in all her raw and fertile splendor." (http://www.goddessgift.com/colin-heaney-art-glass/goddess-willendorf-1.htm) She's probably not the image of yourself you've been taught to honor. At the same time, she's an exquisite image of the roaring, whole, round, mama, goddess most of us are... not a stick figurine resembling an augmented, emaciated, pre-pubescent girl. Our conditioned response to the female form has certainly evolved.
Today for Om School we're getting outside and looking for shapes in nature. Instead of telling A. what I think the shapes we discover mean, I'll ask her to express what they mean to her. Maybe Jung and Campbell were right... maybe universal archetypes exist in the depths of our consciousness. Maybe the Buddha was right... maybe all things are empty of inherent meaning and definitions only arise in relation to everything else. Then again, maybe the only meaning things have is what we give them. Whatever the case may be, I'm hoping that discovering hidden shapes in nature proves to be an awe inspiring adventure.