diff --git a/leansim/main.py b/leansim/main.py
index 55d0af3..e895107 100644
--- a/leansim/main.py
+++ b/leansim/main.py
@@ -3,16 +3,18 @@
 
 def main():
     parser = argparse.ArgumentParser()
-    parser.add_argument('--workers', '-w', default=4, help='Number of workers in value stream.')
-    parser.add_argument('--work', default=20, help='Number of products to make.')
-    parser.add_argument('--duration', default=2, help='Number of time steps each process takes.')
-    parser.add_argument('--batch', default=20, help='Batch size for each worker.')
-    parser.add_argument('--sleep', default=0.2, help='Time to sleep between steps.')
-    # parser.add_argument('--bottleneck', default=False)
+    parser.add_argument('--workers', '-w', default=4, type=int, help='Number of workers in value stream.')
+    parser.add_argument('--work', default=100, type=int, help='Number of products to make.')
+    parser.add_argument('--duration', default=2, type=int, help='Number of time steps each process takes.')
+    parser.add_argument('--batch', default=20, type=int, help='Batch size for each worker.')
+    parser.add_argument('--sleep', default=0.05, type=float, help='Time to sleep between steps.')
+    parser.add_argument('--bottleneck', default=0, type=int, help='Position of bottleneck. If 0, no bottleneck exists.')
+    parser.add_argument('--max_todo', default=None, type=int, help='Maximum worker todo list size. Used for demonstrating pull/kanban system')
+
 
     args = parser.parse_args()
     Workflow.run_chained_process(workers=args.workers, work=args.work, task_duration=args.duration, batch_size=args.batch,
-                                 verbose=True, sleep_time=args.sleep)
+                                 verbose=True, sleep_time=args.sleep, max_todo=args.max_todo, bottleneck_worker=args.bottleneck)
 
 
 
diff --git a/leansim/workflow.py b/leansim/workflow.py
index 2fffb6d..600e0b4 100644
--- a/leansim/workflow.py
+++ b/leansim/workflow.py
@@ -53,17 +53,19 @@ def __repr__(self):
 
         rep += '-----------------------------------------------------------\n'
 
-        for attr in ['total_work', 'wip', 'work_done']:
+        for attr in ['total_work', 'wip']:
             rep += '{}: {}     '.format(attr, getattr(self, attr))
 
         return rep
     
     @classmethod
-    def run_chained_process(cls, work=20, workers=4, verbose=False, sleep_time=0.2, **worker_kwargs):
+    def run_chained_process(cls, work=20, workers=4, verbose=False, sleep_time=0.2, bottleneck_worker=None, **worker_kwargs):
         queue = [Worker(**worker_kwargs) for _ in range(workers)]
         for w1, w2 in zip(queue[:-1], queue[1:]):
             w1.target = w2
         
         workflow = cls(workers=queue)
+        if bottleneck_worker:
+            workflow.workers[bottleneck_worker - 1].task_duration = workflow.workers[0].task_duration * 4
         steps = workflow.process(work=work, verbose=verbose, sleep_time=sleep_time)
         return steps
\ No newline at end of file