diff --git a/Chapter06/snake_functions.py b/Chapter06/snake_functions.py
index deef10852cd06deed313c2ef51bf584cd5dae642..ff803c4f404a7123d015e9a303338c730da7cf05 100644
--- a/Chapter06/snake_functions.py
+++ b/Chapter06/snake_functions.py
@@ -1,12 +1,13 @@
 """
-Helping functions for snakes.
+Helping functions for snakes. 
+Note that snake here is 2-by-N array!
 """
 
 import numpy as np
 import scipy.interpolate
 
 def distribute_points(snake):
-    """ Distributes snake points equidistantly."""
+    """ Distributes snake points equidistantly. Expects snake to be 2-by-N array."""
     N = snake.shape[1]
     
     # Compute length of line segments.