diff --git a/advent_of_code/d9/main.cpp b/advent_of_code/d9/main.cpp
index 55a2f4b..fe64098 100644
--- a/advent_of_code/d9/main.cpp
+++ b/advent_of_code/d9/main.cpp
@@ -67,6 +67,20 @@ int main(){
 
     cout << result << endl;
 
+    // For the second part we need to do some kind of scanning of all points line by line
+    // in which we need to make sure we don't scan points multiple times.
+    // Im thinking of something akin to line segment intersection with a scan line
+    // So keep track of which regions are currently present on the scan line
+    // One region can occur multiple times on the scane line,
+    // so we have to look into which events exist
+
+    // But now we have to keep track of the previous lines all the time as well,
+    // so it is not exactly the same as a scanning line thing
+
+    // I think this doesn't work, in the worst case I think you can have situations
+    // in which each points gets visited n times or n / 2 or something
+
+
     cout << flush;
 
     return 0;