Even if you walk exactly the same route each time - as with a sonnet - the events along the route cannot be imagined to be the same from day to day, as the poet's health, sight, his anticipations, moods, fears, thoughts cannot be the same.
“I think it's a pretty good day if I can get through it without lifting a finger.”
“Using adult stem cells drawn from bone marrow and umbilical cord blood system cells, scientists have discovered new treatments for scores of diseases and conditions such as Parkinson's disease, juvenile diabetes, and spinal cord injuries.”