“Footprints” was a staple of Miles’ late 60’s band, which took the blues form and overall minor tonality to its logical end. This preceded the era of free jazz with it’s abandoning of tonality, bar lines, scales, and most other conventional structures. When you hear Miles’ band from that era, they do a genius job of obscuring all these things while still leaving footprints behind. The tune itself is malleable and has been interpreted in dozens of different ways.