This regular tetrahedron is composed of equilateral triangles on all sides.

World War I was a large-scale war that lasted from 1914 to 1918.

World War II lasted from 1939 to 1945.

Let's pray that World War III does not occur.

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.

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

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