$g ='* * * * * Just  another  Perl  hacker. * * * * *';
$t=length $g;

sub h{
    select $9,$8,$7,pop
}

$|++;
$r="\r".' 'x$t;
print $g;

h(1);

{
    h(.15);
    print " $r\r@{[' 'x(($t-length $g)/2)]}$g";
    do {
        die"$r\n"
    }unless $g=~s/(.)(.)/($1,$2)[rand(2)]/gex;
    redo
}