Sometimes the most profound mathematics comes from playing with simple ideas until they reveal their hidden complexity.
出自北齐·颜之推《颜氏家训·勉学》。博士:指学识渊博的人。一个学识渊博的人打算去买一头驴,可是写了三页纸也没有见到一个“驴”字。这句话常用来讽刺文章文辞繁冗、不得要领、苍白空洞。
A happy person is not a person in a certain set of circumstances, but rather a person with a certain set of attitudes.
农民是最早的环保主义者——他们比任何人都更了解土地。