Now we begin to get into the more formative stages of the beginnings of music as we know it in the Western world. The music of Ancient Greece was built upon tetrachords, stacked fourths and even four note scales. By combining different groupings and orders of the notes found in any of these scales you can open your eyes to different chord voicings and progressions. By applying the scales as a simple progression outline for soloing over you will begin to find more recognisable stress points in the music. When you use these to solo over, don't feel limited by the notes within the scale for your melodic lines. Use your feel. Stretch yourself. Experiment.