List: (cycle at node ). The last node points back to the second node, creating a loop. Phase : slow and fast start at . After steps, they meet at node (inside the cycle). Slow traveled steps, fast traveled steps.
They met inside the cycle. Phase : slow resets to , fast stays at . Both move one step at a time. They meet at node , the cycle start. Return node . This is where the tail ends and the cycle begins.