"I Got Rhythm" is a piece composed by George Gershwin with lyrics by Ira Gershwin and published in 1930, which became a jazz standard. Its chord progression, known as the "rhythm changes", is the foundation for many other popular jazz tunes such as Charlie Parker's and Dizzy Gillespie's bebop standard "Anthropology (Thrivin' on a Riff)". Composition The song came from the musical Girl Crazy, which also includes two other hit songs, "Embraceable You" and "But Not for Me", and has been sung by many jazz singers since. It was originally written as a slow song for Treasure Girl (1928) and found another, faster setting in Girl Crazy. Ethel Merman sang the song in the original Broadway production and Broadway lore holds that George Gershwin, after seeing her opening reviews, warned her never to take a singing lesson. The four-note opening riff bears a striking resemblance to the opening melody of the third movement of William Grant Still's Symphony No. 1, "Afro-American." In the 1920s, Still played in the pit orchestra for Shuffle Along, and speculated that Gershwin may have borrowed the melody from his improvisations in the pit, which were later used in his own symphony. The piece was originally penned in the key of D major. The song melody uses four notes of the five-note pentatonic scale, first rising, then falling. A rhythmic interest in the song is that the tune keeps behind the main pulse, with the three "I got..." phrases syncopated, appearing one beat behind in the first bar, while the fourth phase "Who could..." rushes in to the song. The song's chorus is in a 34-bar AABA form. Its chord progression (although often reduced to a standard 32-bar structure for the sake of improvised solos) is known as the "rhythm changes" and is the foundation for many other popular jazz tunes. The song was used as the theme in Gershwin's last concert piece for piano and orchestra, Variations on "I Got Rhythm", written in 1934. The song has become symbolic of the Gershwins, of swing and of the 1920s. As usual, George Gershwin wrote the melody first and gave it to Ira to set, but Ira found it an unusually hard melody for which to compose lyrics. He experimented for two weeks with the rhyme scheme he felt the music called for — sets of triple rhymes — but found that the heavy rhyming "seemed at