His grandfather died of Creutzfeldt-Jakob disease.

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

He prostrated before the king to show respect.

The ship capsized.

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

Shigeru grows vegetables in the field.

This mutetrahedron has a very unusual shape.

This is a model of a mutetrahedron.