Henry Cowell is one of my favourite composers. I enjoy his compositions opening the possibilities of the piano, and also his modal and oriental scales based works.
I have read many times some parts of his book, one of the bests explaining bitonality, politonality, harmony by seconds, clusters, etc... So, he "tautgh" me many of these concepts.
The first 4 bars of this little piece aren't part of one of his compositions. In fact, it is just the beginning of one of the examples in his book (New Musical Resources), the start point to rework it in politonality. And that's what I've done: a few variations, some tonal, some politonal.