本作品来自scratch社区，非原创作品。 本作品仅仅用于课程教程，由于时间太长，无法找到出处，特此说明。如果有影响，请提醒我。 This work is from scratch community, not original. This work is only used for course, because the time is too long, we can not find the source. Please remind me if there is any impact.
