Also known as "Prog" and "Art House", is a style of the Rock genre that pushes the boundaries of the traditional Rock song structures both musical and vocally, but also lyrically. Progressive blends Rock with sonic and structural elements of jazz, classical, and world. It is similar to Math Rock, in that it is very technical, but is more expansive. Lyrically, high concept albums are typical, taking an entire collection of songs to tell a singular story. This style also is present in the Folk and Metal genres.