Unit square

A unit square is a square with side length equal to $1$ . In a Cartesian coordinate system, the unit square can be viewed as the square with vertices at $(0,0), (0,1), (1,0), (1,1)$ ; likewise, if the concept of the unit square is extended to the complex plane, it can be defined as the square with vertices at $0$ , $1$ , $i$ , and $1 + i$ , where $i$ is the imaginary unit.