sub riffle {
    splice @_, @_/2 - $_, 0, pop
        for 0 .. (@_/2)-1;
    return @_;
}

my @deck = glob "{2,3,4,5,6,7,8,9,T,J,K,Q,A}{C,D,H,S}";

for my $shuffle (1 .. 10) {
    @deck = riffle @deck;
    print "shuffle #$shuffle:\n@deck\n";
}