use strict;
use warnings;

sub splice_insert {
    splice( @_, 2, 2, ('a' .. 'c') );
    print "@_ # after splice\n";
    $_ = '.' for @_;
    print "@_ # after for loop\n";
}

my @a = ( 0 .. 6 );

print "@a   # before subroutine\n";

splice_insert(@a);

print "@a   # after subroutine\n";