save project

snake.py

@@ -61,6 +61,8 @@ while True:
         apple_y = b*30
         apple_y = b*30
     else:
     else:
         position.pop(0)
         position.pop(0)
+    if x<0 or x>630 or y<0 or y>450:
+        exit()
     position.append((x, y))
     position.append((x, y))
     # 将背景图画上去
     # 将背景图画上去
     screen.blit(background, (0, 0))
     screen.blit(background, (0, 0))