industry is good at diligence, but it is barren in playfulness, and it is successful in thinking, and it is ruined with "industry is diligent and barren in playfulness", which means that the depth of study lies in diligence, while the neglect lies in playfulness. Industry is good at diligence and barren in playfulness, which comes from Han Yu's "Persuading to Learn". It means that study is proficient because of diligence, but it is abandoned in the laughter. ...