diff --git a/demo.py b/demo.py
index c6beefd..4d9353b 100644
--- a/demo.py
+++ b/demo.py
@@ -44,7 +44,7 @@
 # r0 can also be calculated from Cn2 and L using the get_r0 function: 
 # r0 = get_r0(Cn2, L)
 r0 = 0.05
-L = 3000
+
 im_size = x.shape[1] # The current version works for square image only
 
 # Generate correlation matrix for tilt. Do this once for each different turbulence parameter.