In the Mahayana Buddhist tradition, it is believed that the drawing was designed by the Buddha himself in order to help ordinary people understand the Buddhist teachings.
The meanings of the main parts of the diagram are:
1. The images in the hub of the wheel represents the three poisons of ignorance, attachment and aversion.
2. The second layer represents karma.
3. The third layer represents the six realms of samsara.
4. The fourth layer represents the twelve links of dependent origination.
5. The fierce figure holding the wheel represents impermanence.
6. The moon above the wheel (top left in the image at right) represents liberation from samsara or cyclic existence.
7. The Buddha pointing to the moon indicates that liberation is possible.
Symbolically, the three inner circles, moving from the center outward, show that the three poisons of ignorance, attachment, and aversion give rise to positive and negative actions; these actions and their results are called karma. Karma in turn gives rise to the six realms, which represent the different types of suffering within samsara.
The fourth and outer layer of the wheel symbolizes the twelve links of dependent origination; these links indicate how the sources of suffering—the three poisons and karma—produce lives within cyclic existence.
The fierce being holding the wheel represents impermanence; this symbolizes that the entire process of samsara or cyclic existence is impermanent, transient, constantly changing. The moon above the wheel indicates liberation. The Buddha is pointing to the moon, indicating that liberation from samsara is possible.