How about using splice?

knoppix@Microknoppix:~$ perl -E '
> @arr = ( 1 .. 6 );
> while ( @arr )
> {
>     ( $x, $y ) = splice @arr, 0, 2;
>     say qq{$x - $y};
> }'
1 - 2
3 - 4
5 - 6
knoppix@Microknoppix:~$
[download]

I hope this is helpful.