The wheel of life
A vivid wheel, clutched by a monster, diagrams exactly how craving spins beings through life after life.
The "wheel of life" (Sanskrit bhavacakra, literally the "wheel of becoming") is one of Buddhism's most recognizable images: a great circle held in the jaws and claws of a fearsome figure, often painted at the entrance of temples. It is a teaching diagram — a single picture meant to show why beings keep being reborn, taking life after life after death, and how that whole process could stop.
The wheel has nested rings. At the very center sit three animals chasing or biting one another: a rooster, a snake, and a pig, standing for greed, hatred, and delusion — the three root drives Buddhism calls the engine of suffering. The next ring shows beings rising to better rebirths or sinking to worse ones. The large spokes divide the wheel into the six realms of rebirth: gods, jealous demigods, humans, animals, hungry ghosts, and hell-beings. The outermost rim shows twelve scenes illustrating "dependent origination" — the step-by-step chain by which ignorance conditions craving, craving conditions clinging, and clinging conditions renewed birth, aging, and death.
The monster gripping the wheel personifies impermanence and death, reminding the viewer that nothing inside the wheel is secure. Importantly, the image is not despairing. Outside the wheel a buddha (an "awakened" being who has understood reality) typically points the way out, signaling that the whole turning cycle has an exit: nirvāṇa, the peace reached when greed, hatred, and delusion are extinguished — not a being's annihilation, but the cooling of the fires that kept the wheel turning. The wheel is thus diagnosis and hope in one frame.