splice(). Here's a snippet for you.

use CGI qw( Tr td div font br );

while ( @cities )
{
    my @row = splice @cities, 0, 4;
    print join( "",
                map( Tr( td( { -width => '25%', },
                             div( { -align => 'center', },
                                  font( { -color => '#2f2cff' },
                                        $_ )
                                  . br() ) ) ),
                     @row ) );
}
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