My four treasures of the study are a fountain pen, a pencil, an eraser, and a ruler.

This ancient proverb, 'know the other side and yourself, and you will not be in danger in a hundred battles', teaches us the importance of understanding ourselves and others.

This is a model of a muoctahedron.

This is a 六角四片四角孔ねじれ正多面體, in other words, a muoctahedron.

Thank you for waiting, here is your grilled eel rice.

The 24-cell is one of the geometric shapes in four dimensions.

The 正二十四胞體 is one of the regular polytopes in four dimensions.

He warned the young people, saying 'At thirty, one should not be careless, at forty, one should not be indecisive.'

He faced difficulties with the spirit of 'one eye, two feet, three gallbladders, four strengths'.