fix a lot of Tkinter imports
diff --git a/Demo/tkinter/matt/animation-simple.py b/Demo/tkinter/matt/animation-simple.py
index 071bde7..4120d66 100644
--- a/Demo/tkinter/matt/animation-simple.py
+++ b/Demo/tkinter/matt/animation-simple.py
@@ -1,4 +1,4 @@
-from Tkinter import *
+from tkinter import *
 
 # This program shows how to use the "after" function to make animation.