I think Rod summarized the falling out between Jorn and Bill
nicely (see Raiding the Icebox by Peter Wollen for more about the
specific disagreement' or, Greil Marcus's Lipstick Traces for
overview of Letterist activities) ... and Eric's mention of
StereoLab's work reminds me of how Jorn has (finally) got his day
in the contemporary zeitgeist ... My thought is that Fluxus
publications reflect an interest in both the Concrete poetry (that
grew from Max Bill's theory of concrete art) and concrete actions
(that is similar to work that arose from Jorn and others). I have
found some tangential connections between Fluxus folks and
Letterists (etc), but nothing really literal (any avtual
connections -- letters/collaborations/meetings? -- that anyone
might know about between Fluxus and CoBrA). Craig Saper