The hollow circle in the diagrams is the root in a major scale, and the hollow circle with a dot in the center is the root in a minor scale. The shapes suggest various ways for you to visualize the basic pattern of the pentatonic scale shown by the Dots. The fretmap that best demonstrates the symmetry of the pentatonic scale is the Diamonds.
|Clock||Dots||Diagonals||N-shape||Diamonds||2 times 3||3 times 2|
The Diagonals show that you can get through the five notes in the pentatonic scale by repeatedly moving five semitones down, starting from the root in major. The sequence then becomes 1-5-2-6-3. The N-shape is a bit awkward to play. The Diamonds are excellent for seeing how the notes connect both horizontally and vertically across the fretboard. The 2 times 3 and 3 times 2 not only look good, they are also very convenient for shifting up or down by one position.