Added a text to demonstrate interaction with other objects.

falling_sand.py

@@ -119,6 +119,8 @@ class FallingSand:
         self.mouse_pos = self.mouse.get_pos()
         self.sand_surface = pygame.Surface(self.settings.window_size)
         self.sand_surface.fill(self.gray)
+        self.text = pygame.font.Font(pygame.font.get_default_font(), 32).render("Hallo, das ist Sand!!!", True, "white")
+        self.sand_surface.blit(self.text, (self.screen.get_width() // 2, self.screen.get_height() // 2))
         self.matrix = pygame.PixelArray(self.sand_surface)
 
         # loading finished