Now, this method should really have a tutorial all of it's own but we'll leave that for the future.
For our outside playing in this example we'll be using two symmetrical scales - the wholetone and diminished scale. The whole tone scale is constructed from only tones (major 2nd intervals) and the diminished is constructed from a tone then a semitone repeated in that order.
Because these scales are constructed from repeating intervals the listener has something consistent to latch onto when we use them for playing out meaning that our phrases sound strong and less random than with other scale material. They are both very effective for creating tension and release.
In my example video I use both scales in a very blatant way which is not really a good thing but I wanted to give you some easily digestible examples to play with. If you listen to Scott Henderson or Wayne Krantz using these scales they are far more discrete and this gives them a more sophisticated sound.
More on this in a future tutorial.