The circle is one of the four fundamental symbols. Without beginning and end, it is fulfilled and complete, so it is a sign of the absolute. Because of its concluded form, circle represents a symbol of protection, which it provides within its borders. So, a circle symbol was used as defensive cordon around cities, temples and tombs. In addition to his function as magical protection, circle is also a marker of completeness, the absence of differentiation and division.
For ancient mathematics circle symbolized the number one and womb, from which all geometric patterns emanate . Ancient Greek term for the principle, embodied by a circle, is the Monad. It represents the number one, the seed, the essence, the foundation, the builder, the unchanging truth and destiny. From circle, Babylonians developed a device for measuring time, split it in 360 degrees, displayed in six sections and named as "shar", word, which in translation means universe, cosmos, world.
From the circle as a symbol of time was born the idea of the cycle and its eternal movement, which is symbolized by the wheel.
Dharma wheel, also known as life cycle or wheel of law, is a symbol that appears within three Indian religions: Hinduism, Jainism and Buddhism. In Hinduism the wheel represents the attribute of Vedic god Vishnu, the symbol of conservation. In Jainism symbol appears on the palm of the hand. And it is one of the oldest Buddhist symbols, part of the iconography from the time of the Buddhist king Ashoka. The symbol consists of three parts: the hub, rims and spokes. The eight spokes symbolize the path of eight noble truths, which represent essence of Buddha’s learning. Spokes symbolize the correct view, intention, speech, action, right livelihood, effort, mindfulness and concentration. According to Buddhist belief a person with wisdom, insights and moral discipline reaches nirvana, the overcoming of ignorance and leaves the cycle of birth and death. Since in Buddhism emphasizes on the practical aspects of the experience, three parts in the centre of the wheel symbolize the "three exercises" of Buddhist meditation.
Circumference of the wheel of Dharma symbolizes the cycle of Samsara, illusion of an endless cycle of birth and death. If an individual wants to achieve nirvana (enlightenment), it is necessary to leave this circle. Therefore, it symbolizes an individuals ability to go through all the obstacles and illusions of the material world. It also symbolizes the movement of the cosmic order and perfection of Dharma (Law), and secondly, it is a metaphor for the soaring spiritual change and development, encouraged by the teachings of Buddha. The importance of this symbol in Buddhism is supported by the fact, that Buddha was symbolized with the wheel of Dharma even before the appearance of his first depiction.