diff --git a/readme.md b/readme.md
--- a/readme.md
+++ b/readme.md
@@ -9,6 +9,8 @@ Modules:
   * Watcher: interpreting sequence of game positions as a sequence of moves.
   * Broadcaster: interfacing with a go server.
 
+Written for Python 3.4.3. Dependencies: Pillow 2.7.0, NumPy 1.9.2.
+  
 
 Graphic
 -------
@@ -32,4 +34,3 @@ Issues:
   * stone shifts
     * stone stops being recognized -> fixable manually and even ignorable
     * stone is recognized at an empty intersection. It can be occupied later for real. What do?
-
diff --git a/src/grid.py b/src/grid.py
--- a/src/grid.py
+++ b/src/grid.py
@@ -31,7 +31,7 @@ class Grid:
     p2=numpy.cross(c,d)
     vanish1=numpy.cross(p1,p2)
     # !! 32 bit int can overflow. keeping it reasonably small. might want to use a cleaner solution
-    vanish1=EPoint.fromProjective(vanish1).toProjective()
+    vanish1=EPoint.fromProjective(vanish1).toProjective() # !! EPoint fails with point in infinity
     
     p3=numpy.cross(a,d)
     p4=numpy.cross(b,c)