String Trio Cello,Violin - Level 2 - Digital Download SKU: A0.1469755 By Katy Perry. By Esther Dean, Katy Perry, Mikkel Eriksen, Sandy Wilhelm, and Tor Erik Hermansen. Arranged by Homco/Crinion. Pop. 7 pages. Homco/Crinion #1047662. Published by Homco/Crinion (A0.1469755). Described as a 'dance-pop self-empowerment anthem,' Firework was a commercially successful release by Katy Perry in 2010. It was meant to inspire young people to become more confident in themselves. In this String Trio Arrangement, the melody is in the violins, while the cello is the rhythmic bass. Make 'em go awe, awe, awe!.