Please explain me parallax method eaisly............

Parallax Method:

When any object is seen from two different positions then there is a change in the position of the object with respect to the background . This phenomenon is named as Parallax. Here distance between two positions is called the basis.

Example

When we hold a pencil in front of us against the background of a wall and look at the pencil first by our left eye A (closing the right eye) and then by our right eye B (closing the left eye), we find that position of pencil changes with respect to the background wall . This is called as Parallax.
Here AB = basis and angle AOB is called parallax angle.
So from the figure angle AOB = b/x where AB=b and AO=BO=x