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sub decomp { @_ = split / /, shift; return [ map { join " ", (shift, shift, $_[0]) } (1..@_/2) ]; }
sub decomp { my $n = 2; # for n+1-uples @_ = split / /, shift; return [ map { $_*=$n; "@_[$_..$_+$n]" } 0..@_/$n-1 ]; }