diff --git a/src/parallel b/src/parallel
index 206d1e3b..8c3005ff 100755
--- a/src/parallel
+++ b/src/parallel
@@ -198,6 +198,7 @@ sub pipe_tee_setup() {
 
 
 sub parcat_script() {
+    # TODO if script fails: Use parallel -j0 --plain --lb cat ::: fifos
     my $script = q'{
 	use Symbol qw(gensym);
 	use IPC::Open3;
@@ -410,27 +411,32 @@ sub pipe_shard_setup() {
     #   cat fifo | user_command
     # Changes:
     #   @Global::cat_prepends
-    my @fifos;
+    my @shardfifos;
+    my @parcatfifos;
     # TODO $opt::jobs should be evaluated (100%)
-    for(0..$opt::jobs-1) {
-#	push @fifos, tmpfifo();
-	push @{$fifos[$_]}, tmpfifo();
+    # TODO $opt::jobs should be number of total_jobs if there are argugemts
+    my $njobs = $opt::jobs;
+    for my $m (0..$njobs-1) {
+	for my $n (0..$njobs-1) {
+	    # sharding to A B C D
+	    # parcatting all As together
+	    $parcatfifos[$n][$m] = $shardfifos[$m][$n] = tmpfifo();
+	}
     }
     my $script = sharder_script();
     # cat foo | sharder sep col fifo1 fifo2 fifo3 ... fifoN
-	my @fif = map { $_->[0] }   @fifos;
-#	::debug("shard",'perl', '-e', $script, ($opt::colsep || ","), $opt::shard, @fif);
-    if(not fork()){
+
+    if(not fork()) {
 	# Let the sharder inherit our stdin
 	# and redirect stdout to null
 	open STDOUT, ">","/dev/null";
-#	exec 'perl', '-e', $script, ($opt::colsep || ","), $opt::shard, @fifos;
-	 @fif = map { $_->[0] }   @fifos;
-	exec 'perl', '-e', $script, ($opt::colsep || ","), $opt::shard, @fif;
+	# The PERL_HASH_SEED must be the same for all sharders
+	# so B::hash will return the same value for any given input
+	$ENV{PERL_HASH_SEED} = $$;
+	exec qw(parallel --block 100k -q --pipe -j), $njobs,
+	    qw(--roundrobin -u perl -e), $script, ($opt::colsep || ","),
+	    $opt::shard, '{}', (map { (':::+', @{$_}) } @parcatfifos);
     }
-
-#    parallel --round-robin $script $opt ::: @fifos[0] ::: @fifos[1]
-
     # For each fifo
     #   (rm fifo1; grep 1) < fifo1
     #   (rm fifo2; grep 2) < fifo2
@@ -440,9 +446,7 @@ sub pipe_shard_setup() {
 	::error("'parcat' must be in path.");
 	::wait_and_exit(255);
     }
-#    @Global::cat_prepends = map { "perl -e $parcat $_ | " } @fifos;
-    @Global::cat_prepends = map { "perl -e $parcat @$_ | " } @fifos;
-#    warn map { "$_\n" } @Global::cat_prepends;
+    @Global::cat_prepends = map { "perl -e $parcat @$_ | " } @parcatfifos;
 }
 
 sub pipe_part_files(@) {
@@ -8219,7 +8223,7 @@ sub wrapped($) {
 	    #   (rm fifo; ... ) < fifo
 	    $command = (shift @Global::cat_prepends). "($command)".
 		(shift @Global::cat_appends);
-	} elsif($opt::pipe) {
+	} elsif($opt::pipe and not $opt::roundrobin) {
 	    # Wrap with EOF-detector to avoid starting $command if EOF.
 	    $command = empty_input_wrapper($command);
 	}