Astronomers spend a lot of time studying blue giants.

A blue supergiant is one of the brightest stars in the universe.

He is working as a clergyman in the church.

He was diagnosed with mental illness.

There are times when we perform calculations with the haversine in trigonometry.

He is a pessimist, always looking at the bad side of the world.

This regular tetrahedron is composed of equilateral triangles on all sides.

He made a model of a regular tetrahedron.

We respect Japanese culture.

We are going on a trip tomorrow.