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.

His grandfather died of Creutzfeldt-Jakob disease.

Chlorofluoromethane is one of the substances that contribute to the destruction of the ozone layer.

I enjoyed the beautiful rural scenery while walking along the ridge.

This mutetrahedron plays a very important role in the world of mathematics.

This mutetrahedron has a very unusual shape.

This is a model of a mutetrahedron.