diff --git a/src/main/java/de/deversmann/gui/GameView.java b/src/main/java/de/deversmann/gui/GameView.java
index e2afa5f..66a14cd 100644
--- a/src/main/java/de/deversmann/gui/GameView.java
+++ b/src/main/java/de/deversmann/gui/GameView.java
@@ -5,8 +5,10 @@ import de.deversmann.facade.Facade;
 import javax.swing.*;
 import java.awt.*;
 import java.io.IOException;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Random;
+import java.util.Set;
 
 public class GameView extends JFrame {