This painting is called conch Mandala.
Conch in the center represents In Buddhism, the conch shell has survived as the original horn trumpet since time immemorial. Ancient Nepali epics describe how each hero of mythical warfare carried a mighty white conch shell, which often bore a personal name.It is one of the main emblems of Vishnu, and his conch bears the name of Panchajanya, meaning ‘having control over the five classes of beings.