my $t = 0;
my @x = grep $t^=1, split /(?<=(.))(?!\1)/, $x;

##</code><code>##

my @x;
push(@x, $1) while $x =~ /((.)\2*)/g;

##</code><code>##

my $t = 0;
my @x = grep $t^=1, $x =~ /((.)\2*)/g;

##</code><code>##

my $t = 0;
my @x = grep $t^=1, map /((.)\2*)/g, $x;