diff --git a/Algorithms/BFSComponentExplorer.h b/Algorithms/BFSComponentExplorer.h
index 768c60012..7bc7ecb30 100644
--- a/Algorithms/BFSComponentExplorer.h
+++ b/Algorithms/BFSComponentExplorer.h
@@ -72,6 +72,14 @@ template <typename GraphT> class BFSComponentExplorer
                                      NodeID node,
                                      unsigned current_component)
     {
+        /*
+           Graphical representation of variables:
+
+           u           v           w
+           *---------->*---------->*
+                            e2
+        */
+
         bfs_queue.emplace(node, node);
         // mark node as read
         m_component_index_list[node] = current_component;
diff --git a/RoutingAlgorithms/BasicRoutingInterface.h b/RoutingAlgorithms/BasicRoutingInterface.h
index 56d1607df..464c08850 100644
--- a/RoutingAlgorithms/BasicRoutingInterface.h
+++ b/RoutingAlgorithms/BasicRoutingInterface.h
@@ -158,6 +158,13 @@ template <class DataFacadeT> class BasicRoutingInterface
         std::pair<NodeID, NodeID> edge;
         while (!recursion_stack.empty())
         {
+            /*
+            Graphical representation of variables:
+
+            edge.first         edge.second
+                *------------------>*
+                       edge_id
+            */
             edge = recursion_stack.top();
             recursion_stack.pop();
 
@@ -175,6 +182,14 @@ template <class DataFacadeT> class BasicRoutingInterface
                     edge_weight = weight;
                 }
             }
+
+            /*
+                Graphical representation of variables:
+
+                edge.first         edge.second
+                    *<------------------*
+                           edge_id
+            */
             if (SPECIAL_EDGEID == smaller_edge_id)
             {
                 for (auto edge_id : facade->GetAdjacentEdgeRange(edge.second))