The heart of ROCK solos: The minor pentatonic scale

Let me first discuss the natural minor scale or simply the minor scale. The minor scale has the scale degrees (as compared to major scale) 1,2,b3,4,5,b6,b7,8. This scale has a dark sound. This is used generally to describe sad situations musically.
The minor pentatonic scale is a subset of the natural minor scale. It takes five notes from the natural minor scale and hence the name "penta-tonic". The scale formula for this scale is 1,b3,4,5,b7. This scale is very very widely used to express rock solos.
The coolest thing about this scale is you can add outside notes to this scale to make it different sounding and it will give you a completely different texture. For example just add a flat fifth note to this scale and you will completely take yourself into the world of blues. Add a flat six or flat two to get different modes of the basic major scale. Try to add notes of your choice and you will yourself see the possibilities coming out. The shapes of the minor pentatonic scale is given below:

The blue notes represent the root notes. The scale shapes are given on the basis of three notes per string. If you are unable to stretch that much, you can slice the shapes with four frets per part. Practice this scale and get yourself familiar with the sound of this scale. It is a bit difficult to get melodious sounds from this scale in the beginning, but with time and practice, things will start to come out in the right direction. Try to add different notes to this scale and you will get melodies quickly.