The paths of our thoughts, fantasies, and dreams are often convoluted. Since ancient times, the labyrinth has been a symbol of life itself with it's paths, crossroads, dead ends, and odysseys. Some such mazes, though full of nooks and crannies, have only one path, one goal, and one exit. Others offer various routes. Written in 2016/17 for saxophone quartet, "Poética del Laberinto" [Poetics of the Labyrinth] by the Spanish composer Alberto Posadas is a cycle about three particularly iconic labyrinths from ancient times to the present day. In contrast to his usual way of composing, these three pieces are also framed by freely determined paths of reminiscence and a successive evolution of the instrumental sound - from uniformity of four soprano saxophones through the diversity of four distinct registers to the dominance of the bass register at the end. Sigma Project or, in other words, the combined talents of Andrés Gomis, Ángel Soria, Alberto Chaves, and Josetxo Silguero, is more than a saxophone quartet. It is a crucial conduit for the instrumental music of the 21st century. The group's joint research and experimentation with Alberto Posadas resulted in a new understanding of the saxophone's possibilities. In search of the sounds Posadas imagined, the players devised groundbreaking techniques to bring the composer's ideas to life - sounds that a saxophone had never made before.