diff --git a/gamecore.cpp b/gamecore.cpp
index 83dc130..a9c782e 100644
--- a/gamecore.cpp
+++ b/gamecore.cpp
@@ -3,7 +3,6 @@
 #include "debug.h"
 
 int GameCore::NODE_SIZE = 25;
-int GameCore::MAX_MOVE_DISTANCE = 200;
 
 GameCore::GameCore()
 {
@@ -92,8 +91,9 @@ void GameCore::render()
     if (graph.get_current_vertex() != NULL)
     {
 	Vertex* v = graph.get_current_vertex();
-	DrawUtils::draw(display, move_template, v->x - MAX_MOVE_DISTANCE / 2, 
-			v->y - MAX_MOVE_DISTANCE / 2);
+	DrawUtils::draw(display, move_template,
+			v->x - Graph::MAX_MOVE_DISTANCE, 
+			v->y - Graph::MAX_MOVE_DISTANCE);
     }
 
 
@@ -124,21 +124,5 @@ void GameCore::on_exit()
 
 void GameCore::on_lbutton_down(int x, int y)
 {
-    Vertex* v = graph.get_current_vertex();
-    Vertex new_v = Vertex();
-    new_v.x = x;
-    new_v.y = y;
-
-#ifdef DEBUG
-    if (v != NULL)
-	cerr << "debug: GameCore::on_lbutton_down(): distance="
-	     << Vertex::distance(*v, new_v) << "\n";
-    else
-	cerr << "debug: GameCore::on_lbutton_down(): distance=0, current_vertex is NULL\n";
-#endif
-
-    if (v != NULL && (Vertex::distance(*v, new_v) > MAX_MOVE_DISTANCE))
-	return;
-
     graph.do_vertex(x, y, NODE_SIZE);
 }
diff --git a/gamecore.h b/gamecore.h
index fae07fb..dd38c3c 100644
--- a/gamecore.h
+++ b/gamecore.h
@@ -45,7 +45,6 @@ class GameCore : public MainEvent
 
     // constants
     static int NODE_SIZE;
-    static int MAX_MOVE_DISTANCE;
 };
 
 #endif
diff --git a/graph.cpp b/graph.cpp
index 57efbaf..7d126eb 100644
--- a/graph.cpp
+++ b/graph.cpp
@@ -4,6 +4,7 @@
 
 using std::abs;
 
+int Graph::MAX_MOVE_DISTANCE = 100;
 
 Graph::Graph()
 {
@@ -75,10 +76,11 @@ void Graph::select_vertex(int x, int y)
 
 void Graph::add_vertex(int x, int y, int size)
 {
-    Vertex* v = new Vertex();
-    v->x = x;
-    v->y = y;
+    if (current_vertex != NULL &&
+	(Vertex::distance(*current_vertex, Vertex(x, y)) > MAX_MOVE_DISTANCE))
+	return;
 
+    Vertex* v = new Vertex(x, y);
     v->x_min = x - size/2;
     v->x_max = x + size/2;
     v->y_min = y - size/2;
diff --git a/graph.h b/graph.h
index de426a0..e7aa325 100644
--- a/graph.h
+++ b/graph.h
@@ -14,6 +14,9 @@ using std::list;
 class Vertex
 {
   public:
+    Vertex(int x, int y)
+    { this->x = x; this->y = y; }
+
     int x;
     int y;
     int x_min;
@@ -44,6 +47,8 @@ class Graph
     void do_vertex(int x, int y, int size);
     Vertex* get_current_vertex() { return current_vertex; }
 
+    static int MAX_MOVE_DISTANCE;
+
  private:
     void add_vertex(int x, int y, int size);
     void select_vertex(int x, int y);