He taught me how to tie a tie.

World War II lasted from 1939 to 1945.

This is the second time he's been late. Well, they say what happens twice will happen three times.

This regular dodecahedron is a geometric shape with perfect symmetry.

This solid is called a regular icosahedron, and it is made up of 20 equilateral triangles.

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

The 120-cell is one of the regular polytopes in four dimensions.

The 正百二十胞體 is one of the regular polytopes in four dimensions.