An important reason for knowing how to play within different formations (forms) of a scale is that it enables you to get higher and lower versions of the same sounds.
The following example demonstrates a lick played in the E form of the A minor pentatonic scale and then in the D form of the same scale. Notice that the notes in the D form are simply a higher version of those in the E form. They are said to be in different octaves. An octave is the distance between higher and lower versions of two notes with the same name.