**1. How Phrases Work in Performance**

Echelon is not a DJ system. It is not built on the metaphor of Deck A and Deck B. It does not mix two sound sources. It does not expect a performer to crossfade between independent musical states. Echelon is a *motion-driven, phrase-based generative performance engine* whose temporal structure emerges from embodied latent physics rather than from a grid or BPM map. The body is the timeline. LIM-RPS is the internal physics. The generative system produces musical material that follows the latent’s curvature. And the UI must express the world in which this physics and music unfold. Decks have no conceptual place here. They belong to a lineage where music exists first and the performer manipulates it second. Echelon belongs to a lineage where the performer exists first and the music is born from that existence. Phrases are the atomic units of musical expression in Echelon, not full tracks. A phrase is a short, coherent musical gesture — generated, conditioned, or prepared — whose beginning, middle, and end correspond to a segment of latent evolution. A phrase is not something you “play” like a song; it is something the system *realizes* from your motion. The phrase is a sonic manifestation of a latent trajectory segment.