"You can put in all the difficulties, jumps, runs, and any other devilish complexities you like, except octave spans and similar features which do not suit the formation of hands"

In this quote, Johann Nepomuk Hummel, a renowned author and pianist, is revealing his thoughts on the technical elements of playing the piano. He mentions that one can include various obstacles and complexities in a piece, such as hard passages, leaps, and runs, however there are specific elements that ought to not be included. Particularly, he mentions octave periods and similar features that do not align with the natural positioning and motion of the hands. This highlights Hummel's understanding of the physical limitations of the human hand and the value of thinking about the ergonomics of piano playing. He emphasizes the need for a structure to be technically tough yet still playable for the performer.