The Federal Republic of Somalia is located in the eastern part of Africa.

The People's Republic of Bangladesh is located in South Asia.

The Luhansk People's Republic is located in the eastern part of Ukraine.

The Donetsk People's Republic is located in the eastern part of Ukraine.

The 正十六胞體 is one of the regular polytopes in four dimensions.

The 正六百胞體 is one of the regular polytopes in four dimensions.

The 16-cell is one of the convex regular polytopes in four dimensions.

The 600-cell is one of the regular polytopes in four dimensions.

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 mutetrahedron has a very unusual shape.