A concerto is a composition in which a solo instrument is played together with an orchestra. Concerti typically have three movements, which are fast, slow and fast, although there are many exceptions. They usually have substantial solo sections, including a cadenza near the end of each movement which allows the soloist to display his or her virtuoso abilities. Soloists almost always play from memory, unlike the musicians in the orchestra, who usually read from sheet music. Among the most common types of concerti are those for the violin and the piano, although they have been written for almost every type of instrument, even including percussion instruments.