$val = unshift ( @{$a->[$i]} );

##</code><code>##

use strict;
for $i(1..4) {
   for $j($i+1..5){
        no strict 'refs';
        if ([eval{"\@a$i"}]->[0] == [eval{"\@a$j"}]->[0]){
            print "Matched one!\n";
            last};
   };
};