diff --git a/py/threads/03.py b/py/threads/03.py
new file mode 100644
index 0000000..254b4f8
--- /dev/null
+++ b/py/threads/03.py
@@ -0,0 +1,22 @@
+import threading
+import time
+import random
+
+def tareaUno():
+  global Done
+  time.sleep (random.random())
+  if not Done:
+    print("Tarea realizada")
+    Done = True
+  else :
+    print ("tarea NO REALIZADA")
+  return
+
+
+Done = False
+hilos = list()
+for i in range(50):
+  t = threading.Thread(target=tareaUno)
+  hilos.append(t)
+  t.start()
+time.sleep(1)
\ No newline at end of file
diff --git a/py/threads/04.py b/py/threads/04.py
new file mode 100644
index 0000000..db2bad4
--- /dev/null
+++ b/py/threads/04.py
@@ -0,0 +1,38 @@
+import threading
+import time
+import random
+
+Done = False
+i = 1
+j = 1
+
+def tareaUno():
+  global Done
+  global i
+  if not Done:
+    print("Tarea %d realizada\n" % i,flush=True)
+    Done = True
+  else :
+    print ("tarea %d NO REALIZADA\n"  % i,flush=True)
+  i +=1
+  return
+
+def tareaDos():
+  global Done
+  global j
+  Done = False
+  print("----- %d tareaDos\n" % j,flush=True)
+  j+=1
+  return
+
+if __name__ == '__main__':
+    hilos = list()
+    for i in range(50):
+      t = threading.Thread(target=tareaUno)
+      if (i % 5) == 0:
+        t = threading.Thread(target=tareaDos)
+      # hilos.append(t)
+      t.start()
+      # time.sleep(0.01)
+
+    time.sleep(5)
\ No newline at end of file