A 'C' Change

If you should search for knowledge To answer the riddle of your self All the books found on every library shelf Might not relieve your puzzle a smidge Because ‘h’ is the difference of self from shelf Search within and you’ll see without eyes. Things happen in a test tube That we can easily observe and explain But anywhere outside of it It’s not quite the same That’s because it’s out in the open Where there’s less control and closure. Some advise taking only two steps Once into and once out of water Supposedly while you’re watching Perpendicular to a flowing stream So firstly you get your feet wet And then you get them dry. Or you take the opposite length Over the adjacent length Then every measured distance Makes each tangent different But if trigonometry was used at Pisa That’s not why the place is famous. So if a princess was in a tower And let’s assume she was a prisoner At least she should have a window Because horizons offer a fine view Then the next time the witch calls her Rupunzel throws down her chair.