diff --git a/ETA.py b/ETA.py
index de06ba3..f580f7e 100644
--- a/ETA.py
+++ b/ETA.py
@@ -605,14 +605,18 @@ fall = np.array( [
     ) for consecutive in fall if len( consecutive ) > 20 # the value might change
 ] ).astype( int )
 
-stairs = np.zeros( ( len( fall ) - 1 , size_x ) )
+stairs = np.zeros( ( len( fall ) , size_x , 2 ) )
 for x in range( size_x ):
     stairs[ : fall[0] , x ] = 0 # TODO: put the mean
     for i in range( len( fall ) - 1 ):
-        stairs[ i , x ] = np.mean( data[
-            calibrations[ 'top' ][ 'y' ][ 'max' ] + fall[ i ] : calibrations[ 'top' ][ 'y' ][ 'max' ] + fall[ i + 1 ],
-            border[ 'x' ][ 'min' ] + x
-        ] )
+        stairs[ i , x ] = [
+            np.mean( data[
+                calibrations[ 'top' ][ 'y' ][ 'max' ] + fall[ i ] : calibrations[ 'top' ][ 'y' ][ 'max' ] + fall[ i + 1 ],
+                border[ 'x' ][ 'min' ] + x
+            ] ),
+            fall[i]
+        ]
+    stairs[ -1 , x ] = [ 0 , fall[ - 1 ] ]
 
 if verbose:
     print( 'ETA flattened' )