In Hinduism, the god is one. Who are Shiva, Vishnu, and Brahma?

In Hinduism, the god is one. Who are Shiva, Vishnu, and Brahma? Once student asked his teacher the same question. The teacher said, “bring me water". The student brought him glass of water. The teacher said, “why did you bring glass I asked you only water?” The student said, “it is not possible to hold the water without glass". The teacher replied, “that is the Answer to your question". The reality is existence but to appreciate existence you need some form of appearance. Shiva, Vishnu, Brahma and Krishna are the different forms of same existence. The Hindus worship the same existence in different forms. Anugrhitoasmi 💛