my $file;
{
  local $/ = undef; # learned something ;}
  $file = <>; #or <FILE>
}
$file =~ tr/\r//d;  #remove carriages

my @items = split /[\t\n]/, $file; #one array of items;
my $rowsize = 3;
my @AoA;
while( @items >= $rowsize ){
  push @AoA, [splice @items, 0, $rowsize]; 
}