北宋的政治家、文学家王安石与他的好友王吉甫经常在一起谈论诗文。一天，王安石对王吉甫说：“我昨夜睡不着，做了一条字谜，‘画时圆，写时方，冬时短，夏时长’。你猜是什么字？”王吉甫略一思索，便猜中了，他不直接说出谜底，也用谜语的形式答道：“东海有条鱼，无头也无? Wang Anshi, a politician and writer in the Northern Song Dynasty, and his good friend Wang Jixi often talked together about poetry. One day, Wang Anshi said to Wang Jiyu: “I couldn’t sleep last night and I had a crossword puzzle. When I was drawing a circle, I wrote the time square, the winter was short, and the summer time was long. What kind of character do you guess?” Wang Jixi thought a bit and guessed However, he did not directly address the mystery and replied in the form of a riddle: "Is there a fish in the East China Sea?