He is an expert in semiotics, and his theories are very profound.

What does this masu symbol mean?

This text is organized using section signs.

Semiotics is the study of signs and symbols used in society and culture.

What does this at sign mean?

The Schläfli symbol is a part of geometry, used to represent the shape of polyhedra.

His advice was very practical.

His target-like way of thinking is hard to understand.

He is my biggest enemy.

What is that target?