diff --git a/thermopi/screen.py b/thermopi/screen.py
index 7b22ec0..155dc2c 100644
--- a/thermopi/screen.py
+++ b/thermopi/screen.py
@@ -26,7 +26,10 @@ def main(windowed_mode):
 
         mouse_pos = pygame.mouse.get_pos()
         window.fill((0, 0, 0))
-        pygame.draw.line(window, (255, 255, 255), (720/2, 720/2), mouse_pos, 15)
+        pygame.draw.line(window, (255, 255, 255), (0, 0), mouse_pos, 10)
+        pygame.draw.line(window, (255, 255, 255), (0, 720), mouse_pos, 10)
+        pygame.draw.line(window, (255, 255, 255), (720, 720), mouse_pos, 10)
+        pygame.draw.line(window, (255, 255, 255), (720, 0), mouse_pos, 10)
 
         pygame.display.flip()