diff --git a/drawutils.cpp b/drawutils.cpp
index 0e42991..63877c0 100644
--- a/drawutils.cpp
+++ b/drawutils.cpp
@@ -51,7 +51,7 @@ bool DrawUtils::draw(SDL_Surface* dest, SDL_Surface* drawable, int x, int y,
     return true;
 }
 
-void DrawUtils::draw_line(Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint16 width, Uint32 colour, SDL_Surface* dest)
+void DrawUtils::draw_line(SDL_Surface* dest, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint16 width, Uint32 colour)
 {
     float dx, dy, len;
     float cx, cy; // our current coords
diff --git a/drawutils.h b/drawutils.h
index 119dd73..cfe2ec1 100644
--- a/drawutils.h
+++ b/drawutils.h
@@ -17,7 +17,7 @@ class DrawUtils
     static bool draw(SDL_Surface* dest, SDL_Surface* drawable, int x, int y);
     static bool draw(SDL_Surface* dest, SDL_Surface* drawable, int x, int y, 
 		     int x2, int y2, int w, int h);
-    static void draw_line(Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint16 width, Uint32 colour, SDL_Surface* dest);
+    static void draw_line(SDL_Surface* dest, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint16 width, Uint32 colour);
 
     // transpare (v) - to make transparent
     static bool transpare(SDL_Surface* surface, int r, int g, int b);
diff --git a/gamecore.cpp b/gamecore.cpp
index f242b1c..3291705 100644
--- a/gamecore.cpp
+++ b/gamecore.cpp
@@ -67,13 +67,13 @@ void GameCore::render()
 {
     DrawUtils::draw(display, background, 0, 0);
 
-    list<Vertex> vertices = graph.get_vertices();
+    list<Vertex*> vertices = graph.get_vertices();
     list<Edge> edges = graph.get_edges();
 
-    for (list<Vertex>::iterator cursor = vertices.begin();
+    for (list<Vertex*>::iterator cursor = vertices.begin();
 	 cursor != vertices.end(); cursor++)
     {
-	Vertex v = *cursor;
+	Vertex v = *(*cursor);
 	DrawUtils::draw(display, node, v.x_min, v.y_min);
     }
 
@@ -81,7 +81,8 @@ void GameCore::render()
 	 cursor != edges.end(); cursor++)
     {
 	Edge e = *cursor;
-	DrawUtils::draw_line(e.a.x, e.a.y, e.b.x, e.b.y, 2, 0x000000, display);
+	DrawUtils::draw_line(display, e.a->x, e.a->y, e.b->x, e.b->y, 2,
+			     0x000000);
     }
 
     SDL_Flip(display);
diff --git a/graph.cpp b/graph.cpp
index 7c54d35..4481bfe 100644
--- a/graph.cpp
+++ b/graph.cpp
@@ -1,4 +1,28 @@
 #include "graph.h"
+#include <cmath>
+
+using std::abs;
+
+#ifdef DEBUG
+#include <iostream>
+using std::cerr;
+#endif
+
+
+Graph::Graph()
+{
+    last_vertex = NULL;
+}
+
+Graph::~Graph()
+{
+    for (list<Vertex*>::iterator cursor = vertices.begin();
+	 cursor != vertices.end(); cursor++)
+    {
+	Vertex* v = *cursor;
+	delete v;
+    }
+}
 
 bool Graph::vertex_present(int x, int y, int size)
 {
@@ -9,17 +33,22 @@ bool Graph::vertex_present(int x, int y, int size)
     int y_min = y - delta;
     int y_max = y + delta;
 
-    for (list<Vertex>::iterator cursor = vertices.begin();
+    for (list<Vertex*>::iterator cursor = vertices.begin();
 	 cursor != vertices.end(); cursor++)
     {
-	Vertex v = *cursor;
-	if (((x_min >= v.x_min && x_min <= x_max) &&
-	     ((y_min >= v.y_min && y_min <= y_max) ||
-	      (y_max >= v.y_min && y_max <= y_max))) ||
-	    ((x_max >= v.x_min && x_max <= x_max) &&
-	     ((y_min >= v.y_min && y_min <= y_max) ||
-	      (y_max >= v.y_min && y_max <= y_max))))
+	Vertex v = *(*cursor);
+	if (((x_min >= v.x_min && x_min <= v.x_max) &&
+	     ((y_min >= v.y_min && y_min <= v.y_max) ||
+	      (y_max >= v.y_min && y_max <= v.y_max))) ||
+	    ((x_max >= v.x_min && x_max <= v.x_max) &&
+	     ((y_min >= v.y_min && y_min <= v.y_max) ||
+	      (y_max >= v.y_min && y_max <= v.y_max))))
+	{
+#ifdef DEBUG
+    cerr << "debug: Graph::vertex_present(): vertex present at x=" << v.x << ", y=" << v.y << "\n";
+#endif
 	    return true;
+	}
     }
 
 	return false;
@@ -27,18 +56,25 @@ bool Graph::vertex_present(int x, int y, int size)
 
 void Graph::add_vertex(int x, int y, int size)
 {
-    Vertex v;
-    v.x = x;
-    v.y = y;
+    Vertex* v = new Vertex();
+    v->x = x;
+    v->y = y;
 
-    v.x_min = x - size/2;
-    v.x_max = x + size/2;
-    v.y_min = y - size/2;
-    v.y_max = y + size/2;
+    v->x_min = x - size/2;
+    v->x_max = x + size/2;
+    v->y_min = y - size/2;
+    v->y_max = y + size/2;
 
-    if (vertex_present(v.x, v.y, 25)) return;
+    if (vertex_present(v->x, v->y, 25)) return;
 
     vertices.push_back(v);
+
+    if (last_vertex == NULL)
+    {
+	last_vertex = v;
+	return;
+    }
+
     Edge e;
     e.a = last_vertex;
     e.b = v;
@@ -46,3 +82,11 @@ void Graph::add_vertex(int x, int y, int size)
     last_vertex = v;
 }
 
+
+float Vertex::distance(Vertex a, Vertex b)
+{
+    float dy = abs(static_cast<float>(b.y) - a.y);
+    float dx = abs(static_cast<float>(b.x) - a.x);
+    if (dx == 0) return 0;
+    return dy/dx;
+}
diff --git a/graph.h b/graph.h
index f7fe32c..1332868 100644
--- a/graph.h
+++ b/graph.h
@@ -11,37 +11,41 @@
 
 using std::list;
 
-struct Vertex
+class Vertex
 {
+  public:
     int x;
     int y;
     int x_min;
     int x_max;
     int y_min;
     int y_max;
+
+    static float distance(Vertex a, Vertex b);
 };
 
 struct Edge
 {
-    Vertex a;
-    Vertex b;
+    Vertex* a;
+    Vertex* b;
 };
 
 class Graph
 {
  public:
-    Graph() {}
+    Graph();
+    ~Graph();
 
     bool vertex_present(int x, int y, int size);
 
-    list<Vertex> get_vertices() { return vertices; }
+    list<Vertex*> get_vertices() { return vertices; }
     list<Edge> get_edges() { return edges; }
 
     void add_vertex(int x, int y, int size);
 
  private:
-    Vertex last_vertex;
-    list<Vertex> vertices;
+    Vertex* last_vertex;
+    list<Vertex*> vertices;
     list<Edge> edges;
 };