a page from the sequence
Zr + 4HCl → ZrCl4 + 2H2
U + 3F2 → UF6
by Roberto Altmann, a Cuban-born Lettriste, published in Cuban revista Signos #3 (1970).
more information: (1) & (2), courtesy of Domingos Isabelinho's blog,
& a slide-show put up by The Modesto Kid.
thanks, Mike Jacobson, for showing me this.