On the other hand, the later music—and a few earlier pieces such as "Continuum"—treats the pulse as a musical atom, a common denominator, a basic unit, which cannot be divided further. Different rhythms appear through multiplications of the basic pulse, rather than divisions: this is the principle of African music seized on by Ligeti. It also appears in the music of Philip Glass, Steve Reich and others; and significantly it shares much in common with the additive rhythms of Balkan folk music, the music of Ligeti’s youth. He described the music of Conlon Nancarrow, with its extremely complex explorations of polyrhythmic complexity, as "the greatest discovery since Webern and Ives... something great and important for all music history! His music is so utterly original, enjoyable, perfectly constructed, but at the same time emotional... for me it's the best music of any composer living today."