diff --git a/pixelocr/utils.py b/pixelocr/utils.py
index c1fc320..df3d9a4 100644
--- a/pixelocr/utils.py
+++ b/pixelocr/utils.py
@@ -15,6 +15,8 @@
 
 
 import functools
+import itertools
+
 
 def cached_property(fun):
     """A memoize decorator for class properties."""
@@ -36,3 +38,9 @@ def collect_iterable(func):
     def collect(*args, **kwargs):
         return list(func(*args, **kwargs))
     return collect
+
+
+def pairwise(iterable):
+    a, b = itertools.tee(iterable)
+    next(b, None)
+    return itertools.zip_longest(a, b)