translation.en: This is actually a picture of the printing mechanism for another machine of his, called the Difference Engine No. 2, which he never built, but which the Science Museum did build in the '80s and '90s.
translation.zh: 这是一幅关于另外一个机器的打印原理的图片 名叫“差分机2号” 他从没建造出来,不过科学博物馆 在80和90年代造出来了