no strict;
no warnings;
my @things = ( 1, 2, 3, "and", 4, 5);
my @bucket;
my $counter = 0;
foreach my $elt ( @things )
{
  if ( $elt ne "and" )
  {
     push ( $elt, @{ $bucket[$counter] } );
  }
  if ( $elt eq "and" )
  {
     $counter++;
  }
}