diff --git a/src/main/java/lab/BulletAnimated.java b/src/main/java/lab/BulletAnimated.java
index 294ad2224d36c995a397101beddad77507592ede..3f80184b5b0aa01392a08b64dfaf85fb90544fe0 100644
--- a/src/main/java/lab/BulletAnimated.java
+++ b/src/main/java/lab/BulletAnimated.java
@@ -5,13 +5,11 @@ import javafx.geometry.Rectangle2D;
 import javafx.scene.canvas.GraphicsContext;
 import javafx.scene.image.Image;
 
-public class BulletAnimated {
+public class BulletAnimated extends WorldEntity implements CollisionAble {
 
-	private Point2D position;
 	private Point2D start;
 	private Point2D speed;
 	private Point2D initialSpeed;
-	private double size;
 	private double mass = 2;
 	private double strenghtOfCannon = .1;
 	private double cannonLength = 100;
@@ -22,7 +20,6 @@ public class BulletAnimated {
 	private double dragCoefficient = 0.47;
 	
 	private Image image;
-	private World world;
 	private Cannon cannon;
 
 	public BulletAnimated(World world, Cannon cannon) {
@@ -30,17 +27,16 @@ public class BulletAnimated {
 	}
 
 	public BulletAnimated(World world, Cannon cannon, Point2D start, Point2D speed, double size) {
+		super(world, start, new Point2D(size, size));
 		this.start = start;
-		this.position = this.start;
 		this.initialSpeed = speed;
 		this.speed = speed;
-		this.size = size;
-		this.world = world;
 		this.cannon = cannon;
 		image = new Image(getClass().getResourceAsStream("fireball-transparent.gif"), size, size,
 				true, true);
 	}
-
+	
+	@Override
 	public void draw(GraphicsContext gc) {
 		gc.save();
 		Point2D canvasPosition = world.getCanvasPoint(position);
@@ -48,6 +44,7 @@ public class BulletAnimated {
 		gc.restore();
 	}
 
+	@Override
 	public void simulate(double deltaT) {
 		double timeStep = deltaT * 1000;
 		if (accelerate && start.distance(position) < cannonLength) {
@@ -66,9 +63,9 @@ public class BulletAnimated {
 		}
 		if (!hitToGround) {
 			position = position.add(speed);
-			if (!accelerate && position.getY() <= size / 2) {
+			if (!accelerate && position.getY() <= dimension.getY() / 2) {
 				hitToGround = true;
-				position = new Point2D(position.getX(), size / 2);
+				position = new Point2D(position.getX(), dimension.getX() / 2);
 			}
 		} else {
 			reload();
@@ -77,8 +74,16 @@ public class BulletAnimated {
 		
 	}
 
+	@Override
 	public Rectangle2D getBoundingBox() {
-		return new Rectangle2D(position.getX(), position.getY(), size, size);
+		return new Rectangle2D(position.getX(), position.getY(), dimension.getX(), dimension.getY());
+	}
+	
+	@Override
+	public void hitBy(CollisionAble other) {
+		if (other instanceof Dragon) {
+			reload();
+		}
 	}
 	
 	public boolean overlaps(Dragon dragon) {
diff --git a/src/main/java/lab/Cannon.java b/src/main/java/lab/Cannon.java
index b46745dc0779c5152639f0c4c9815c34f80d56fa..3c5cc23f85c02ec7c01cd6b6a0e305182b26a798 100644
--- a/src/main/java/lab/Cannon.java
+++ b/src/main/java/lab/Cannon.java
@@ -5,24 +5,19 @@ import javafx.scene.canvas.GraphicsContext;
 import javafx.scene.paint.Color;
 import javafx.scene.transform.Affine;
 
-public class Cannon {
+public class Cannon extends WorldEntity{
 
 	private int direction=-1;
 	private double angle = 0;
-	private Point2D position;
-	private Point2D size;
-	private World world;
 	
 	
 	 
 
 	public Cannon(World world, Point2D position, Point2D size) {
-		super();
-		this.world = world;
-		this.position = position;
-		this.size = size;
+		super(world, position, size);
 	}
 
+	@Override
 	public void simulate(double timeStep) {
 		angle = angle + direction*80*timeStep;
 		if(angle <=-90 || angle >= 0) {
@@ -30,16 +25,17 @@ public class Cannon {
 		}
 	}
 	
+	@Override
 	public void draw(GraphicsContext gc) {
 		gc.save();
 		Point2D worldPosition = world.getCanvasPoint(position);
 		gc.setFill(Color.BROWN);
-		gc.fillRect(worldPosition.getX()-10, worldPosition.getY()+size.getY(), size.getX()+20, size.getY()/2);
-		gc.fillOval(worldPosition.getX()-20, worldPosition.getY()+size.getY()/2, 40, 40);
-		gc.fillOval(worldPosition.getX()+size.getX(), worldPosition.getY()+size.getY()/2, 40, 40);
-		gc.setTransform(new Affine(Affine.rotate(angle, worldPosition.getX(), worldPosition.getY()+size.getY()/2)));
+		gc.fillRect(worldPosition.getX()-10, worldPosition.getY()+dimension.getY(), dimension.getX()+20, dimension.getY()/2);
+		gc.fillOval(worldPosition.getX()-20, worldPosition.getY()+dimension.getY()/2, 40, 40);
+		gc.fillOval(worldPosition.getX()+dimension.getX(), worldPosition.getY()+dimension.getY()/2, 40, 40);
+		gc.setTransform(new Affine(Affine.rotate(angle, worldPosition.getX(), worldPosition.getY()+dimension.getY()/2)));
 		gc.setFill(Color.BLACK);
-		gc.fillRect(worldPosition.getX(), worldPosition.getY(), size.getX(), size.getY());
+		gc.fillRect(worldPosition.getX(), worldPosition.getY(), dimension.getX(), dimension.getY());
 		gc.restore();
 	}
 
diff --git a/src/main/java/lab/CollisionAble.java b/src/main/java/lab/CollisionAble.java
new file mode 100644
index 0000000000000000000000000000000000000000..7ab131c58846b0d4c303f7fae1568df479fd1999
--- /dev/null
+++ b/src/main/java/lab/CollisionAble.java
@@ -0,0 +1,14 @@
+package lab;
+
+import javafx.geometry.Rectangle2D;
+
+public interface CollisionAble {
+	default boolean overlaps(CollisionAble other) {
+		return getBoundingBox().intersects(other.getBoundingBox());
+	}
+
+	void hitBy(CollisionAble other);
+	
+	Rectangle2D getBoundingBox();
+	
+}
diff --git a/src/main/java/lab/Dragon.java b/src/main/java/lab/Dragon.java
index 216628afbd03d95d4896abc8b5175efcb25709c8..5592acfa68668c94dc0b74205b9ac05aa12a5236 100644
--- a/src/main/java/lab/Dragon.java
+++ b/src/main/java/lab/Dragon.java
@@ -4,30 +4,23 @@ import javafx.geometry.Point2D;
 import javafx.geometry.Rectangle2D;
 import javafx.scene.canvas.GraphicsContext;
 
-public class Dragon {
-	
-	private Point2D position;
+public class Dragon extends WorldEntity implements CollisionAble{
 	
 	private Point2D speed;
 	
-	private final World world;
-		
-	private final double size = 45;
-
+	
 	public Dragon(World world, Point2D position, Point2D speed) {
-		super();
-		this.world = world;
-		this.position = position;
+		super(world, position, new Point2D(45, 45));
 		this.speed = speed;
 	}
 
-	
+	@Override
 	public void draw(GraphicsContext gc) {
 		Point2D canvasPosition = world.getCanvasPoint(position);
-		gc.drawImage(Constants.DRAGON_IMAGE, canvasPosition.getX(), canvasPosition.getY(), size, size);
+		gc.drawImage(Constants.DRAGON_IMAGE, canvasPosition.getX(), canvasPosition.getY(), dimension.getX(), dimension.getY());
 	}
 
-
+	@Override
 	public void simulate(double timeDelta) {
 		double timeDeltaS = timeDelta;
 		double newX = (position.getX() + speed.getX() * timeDeltaS + world.getWidth()) % world.getWidth(); 
@@ -36,8 +29,16 @@ public class Dragon {
 	}
 
 
+	@Override
 	public Rectangle2D getBoundingBox() {
-		return new Rectangle2D(position.getX(), position.getY(), size, size);
+		return new Rectangle2D(position.getX(), position.getY(), dimension.getX(), dimension.getY());
+	}
+	
+	@Override
+	public void hitBy(CollisionAble other) {
+		if (other instanceof BulletAnimated) {
+			hit();
+		}
 	}
 
 
diff --git a/src/main/java/lab/DrawableSimulable.java b/src/main/java/lab/DrawableSimulable.java
new file mode 100644
index 0000000000000000000000000000000000000000..41a64a42469431996581f9637def94769cca572e
--- /dev/null
+++ b/src/main/java/lab/DrawableSimulable.java
@@ -0,0 +1,9 @@
+package lab;
+
+import javafx.scene.canvas.GraphicsContext;
+
+public interface DrawableSimulable {
+	void simulate(double deltaT);
+	
+	void draw(GraphicsContext gc);
+}
\ No newline at end of file
diff --git a/src/main/java/lab/World.java b/src/main/java/lab/World.java
index c531c516d183793f4bc8eb3c381b6856c967e25f..80e70a382db739b350192fd77ae00100e0beba7b 100644
--- a/src/main/java/lab/World.java
+++ b/src/main/java/lab/World.java
@@ -6,19 +6,19 @@ import javafx.scene.canvas.GraphicsContext;
 public class World {
 	private double width;
 	private double height;
-	private BulletAnimated bulletAnimatted;
-	private Cannon cannon;
-	private Dragon[] dragons;
+
+	private DrawableSimulable[] objects;
 
 	public World(double width, double height) {
 		super();
 		this.width = width;
 		this.height = height;
-		cannon = new Cannon(this, new Point2D(50, 50), new Point2D(100, 20));
-		bulletAnimatted = new BulletAnimated(this, cannon, new Point2D(30, 60), new Point2D(0, 0), 40);
-		dragons = new Dragon[] { new Dragon(this, new Point2D(50, 200), new Point2D(100, 5)),
+		Cannon cannon = new Cannon(this, new Point2D(50, 50), new Point2D(100, 20)); 
+		objects = new DrawableSimulable[] { new Dragon(this, new Point2D(50, 200), new Point2D(100, 5)),
 				new Dragon(this, new Point2D(50, 230), new Point2D(60, 5)),
-				new Dragon(this, new Point2D(50, 270), new Point2D(-50, 20)) };
+				new Dragon(this, new Point2D(50, 270), new Point2D(-50, 20)),
+				new BulletAnimated(this, cannon, new Point2D(30, 60), new Point2D(0, 0), 40),
+				cannon				};
 	}
 
 	public Point2D getCanvasPoint(Point2D worldPoint) {
@@ -27,22 +27,27 @@ public class World {
 
 	public void draw(GraphicsContext gc) {
 		gc.clearRect(0, 0, width, height);
-		cannon.draw(gc);
-		bulletAnimatted.draw(gc);
-		for(Dragon dragon: dragons) {
-			dragon.draw(gc);
+		for(DrawableSimulable obj: objects) {
+			obj.draw(gc);
 		}
+		
 	}
 
 	public void simulate(double timeDelta) {
-		bulletAnimatted.simulate(timeDelta);
-		cannon.simulate(timeDelta);
-		for(Dragon dragon: dragons) {
-			if (bulletAnimatted.overlaps(dragon)) {
-				dragon.hit();
-				bulletAnimatted.reload();
+		for(DrawableSimulable obj: objects) {
+			obj.simulate(timeDelta);
+		}
+		for (DrawableSimulable i: objects) {
+			if (i instanceof CollisionAble obj1) {
+				for (DrawableSimulable ii: objects) {
+					if (i != ii && ii instanceof CollisionAble obj2) {
+						if (obj1.overlaps(obj2)) {
+							obj1.hitBy(obj2);
+							obj2.hitBy(obj1);
+						}
+					}
+				}
 			}
-			dragon.simulate(timeDelta);
 		}
 	}
 
diff --git a/src/main/java/lab/WorldEntity.java b/src/main/java/lab/WorldEntity.java
new file mode 100644
index 0000000000000000000000000000000000000000..ebdb8e32013b095acc9dc24510e12657792db6c4
--- /dev/null
+++ b/src/main/java/lab/WorldEntity.java
@@ -0,0 +1,16 @@
+package lab;
+
+import javafx.geometry.Point2D;
+
+public abstract class WorldEntity implements DrawableSimulable {
+	protected Point2D position;
+	protected final Point2D dimension;
+	protected final World world;
+	
+	public WorldEntity(World world, Point2D position, Point2D dimension) {
+		this.world = world;
+		this.position = position;
+		this.dimension = dimension;
+	}
+	
+}