$str = "of course, japhy thought of this one";
$parts = 3;  # ooh, not 2!
$len = int(length($str)/$parts);

while (--$parts and $str =~ s{( ?)([^ ]*)(?<=^.{$len})([^ ]*)( ?)}
  { length($2) < length($3) ? "\n$2$3$4" : "$1$2$3\n" }e
) {
  push @parts, ($str =~ s/(.*\n?)// and $1);
}

$str = join("", @parts) . $str;

print $str;

__END__
of course,
japhy thought
of this one
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