Along with the gradual displacement of the voice in favor of stronger, clearer melodies, counterpoint also typically became a decorative flourish, often used near the end of a work or for a single movement. In its stead, simple patterns, such as arpeggios and, in piano music, Alberti bass (an accompaniment with a repeated pattern typically in the left hand), were used to liven the movement of the piece without creating a confusing additional voice. The now-popular instrumental music was dominated by several well-defined forms: the sonata, the symphony, and the concerto, though none of these were specifically defined or taught at the time as they are now in music theory. All three derive from sonata form, which is both the overlying form of an entire work and the structure of a single movement. Sonata form matured during the Classical era to become the primary form of instrumental compositions throughout the 19th century.