Pat's solo on 'Footprints' is a great showcase for his fondness for creating many different sounds over fairly static chords. As the solo progresses, and the energy builds, he begins to introduce more tension by the use of substitute scales and related pentatonics. The tensions gradually move from mild dissonance in the first few choruses (nat. 7, nat. 6, b6 on Cmin) to extreme dissonance in the later choruses (b9 on Cmin). The result is an exciting solo which masterfully builds tension and energy throughout.