Wheel of Life (sanskr. bhavacakra, tib. srid pa’i ‘khor lo — wheel of dependent origination) — the embodiment of samsara in the Buddhist view in the form of a circle, the Buddhist doctrine of cause and effect (sanskr. pratitya-samutpada), which Buddha realized under the bodhi tree.
The wheel on the thangka depicts the whole existence of sentient beings, including symbolic image of 12 links of dependent origination, and other Buddhist cosmological and astrological structures.
In the image, wheel of life is compressed in the claws by demon of death Mara — the Yama. This means that the laws of cause and effect operate in the field of passions (sanskr. kama-dhatu).