He drew an equilateral triangle shape.

He made a model of a regular tetrahedron.

This orthophoto shows the details of the terrain very clearly.

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

He is an expert in orthoepy, teaching pronunciation.

A positive-definite matrix is an important concept in linear algebra.

Freedom of expression is one of the fundamental rights of democracy.

He was involved in the development of guided missiles.

I live in Jyväskylä, a city in Finland.

He is a celebrity in Japan.