TOOL released "Lateralus," their third studio album and what many consider the greatest progressive metal album ever made. Even measured against the already extraordinary "Ænima," this record represented a quantum leap — deeper into polyrhythm, Fibonacci-sequence song architecture, Jungian psychology, and Maynard James Keenan's most cryptic and profound lyrical work. Adam Jones crafted guitar tones of alien beauty; Danny Carey's drumming — mathematically precise yet emotionally overwhelming — made complex time signatures feel inevitable; Justin Chancellor's bass provided the harmonic and emotional foundation the whole structure rested upon. The title track alone, structurally encoded with the Fibonacci sequence so that the syllable counts of each vocal section mirror 1, 1, 2, 3, 5, 8, 13 before spiraling inward, is studied in universities as an example of mathematics expressed through sound. "Lateralus" debuted at number one on the Billboard 200, selling over 555,000 copies in its first week, and won the Grammy Award for Best Metal Performance for "Schism." In the decades since, it has only grown in stature. There is no ceiling on what it means.
