He made a model of a regular dodecahedron.

He made a model of a regular icosahedron.

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

The ritsuryō system was a system that ruled ancient Japanese society.

All members of the uniformed group have undergone rigorous training.

My father works at a steelworks.

There are many common yarrows blooming in my garden.

The system of provinces was a part of the ancient political system in Japan.

Sexual assault should never be tolerated.

Invasive species can have a major impact on the natural environment.