四勿：“非礼勿视，非礼勿听，非礼勿言，非礼勿动。”四端：“恻隐之心，仁之端也；羞恶之心，义之端也；辞让之心，礼之端也；是非之心，智之端也。”颜渊的“四勿”，要牢记心里；下工夫闲静存诚，克服外部的干扰以修养心性；孟子的“四端”，要尽力扩充，下工夫格物致知，由近及远，推己及人。
Art should provoke, not just decorate.
The first duty of a storyteller is to tell a story.
In the world of mathematics, every question leads to another, creating an endless web of knowledge that connects all areas of science.