--- a/mamba/mutators.py	Sun Sep 11 17:26:05 2011 +0200
+++ b/mamba/mutators.py	Sun Sep 11 17:39:58 2011 +0200
@@ -1,3 +1,33 @@
 """Mutations to apply to images when they're loaded."""
 
+from pygame.transform import rotate
 
+
+class Mutator(object):
+
+    def __init__(self, func, *args):
+        self._func = func
+        sefl._args = args
+
+    def __call__(self, image):
+        return func(image, *args)
+
+    def __hash__(self):
+        return hash((id(self._func), self._args))
+
+    def __eq__(self, other):
+        return (self._func is other.func) and self._args == other._args
+
+NULL = Mutator(lambda x: x)
+
+# sprites mutators
+RIGHT = NULL
+DOWN = Mutator(rotate, 90)
+LEFT = Mutator(rotate, 180)
+UP = Mutator(rotate, -90)
+
+# tile mutators
+TL = NULL
+BL = Mutator(rotate, -90)
+TR = Mutator(rotate, 90)
+BR = Mutator(rotate, 180)