几个月前的一天，正在读一本电子版的“宝书”。突然收到提示到楼下取包裹。打开后，大惊，竟然是来自加州女儿的礼物，纸版的同一本“宝书”。“撞车”了，哈。

前天，将这本珍贵的宝书，转送给了多伦多的一位小朋友：

今天，读到了宝书的最后一章，关于 Cantor 的贡献。很高兴曾去过他出生和童年的地方俄罗斯的圣彼得堡。读着读着，突然一闪念，既然 √2 是无理数，那么那些数字的随机性怎样呢？

马上搜一下，不得了，居然是个让数学家汗颜的尚未证明的问题。

https://www2.lbl.gov/Science-Articles/Archive/pi-random.html

In fact, not a single naturally occurring math constant has been proved normal in even one number base, to the chagrin of mathematicians. While many constants are believed to be normal -- including pi, the square root of 2, and the natural logarithm of 2, often written "log(2)" -- there are no proofs.