The two years following Clarissa, tentative and baffling, with patches of sterile deadlock, were dominated by their most ambitious and demanding product, The Rivers of Hell.  This commission for their first European visit from the crack New York modern-music ensemble Speculum Musicae put me on my mettle in a frightening way.  In response I wrote with blood sweat and tears what seemed to me an extreme of rigorous constructivistic hideousness (but I meant it;  every note) — right back to First Concerto for Orchestra. 

Alongside / simultaneous, ran the other principal commission of this time, Hymn for Voices — its complement, all (well, mostly) sweetness and light, euphoria and euphony — on a florilège of texts (Eliot, nonsense, Sartre, Valéry, Ruskin, d'Annunzio) that culminate in extended wordless ecstasy à la Strauss. 

Both pieces grew in opposite directions from a common core of basic material.