1: Node[data: head, next node: null] 2: Node[data: tail, next node: null] 3: Node[data: head, next node: Node[data: tail, next node: null]] 4: Node[data: middle, next node: null] 5: Node[data: head, next node: Node[data: middle, next node: Node[data: tail, next node: null]]] 6: tail found: Node[data: tail, next node: null]