high, with B and E in octaves and A, D, and G in unisons: The cuatro is composed of several parts that work together to formulate the distinguishable sound of the instrument: Clavijero (pegbox): This is found at the head of the cuatro, which allows the instrument's strings to be tuned Cejuela (nut or hueso): This is found on both ends of the cuatro, close to the head of the instrument, and in the overall body of it. It helps keep the strings in place as well as aid in the tuning process of the instrument. Trastes (fret): There are 18 to 20 frets in a traditional Puerto Rican Cuatro. Diapasón (diapason): Diapason is an addition of the cuatro that is placed under the frets, to allow the musician comfort to the hand and a grasp whilst he/she is playing. Rosetas (rosette): This is a circular ornament that is present at the mouth of the instrument. Although this is allows cuatros to be distinguishable, the actual function that these serve in the instrument is for feedback prevention. Cuerdas (string): The strings are the main element that is in charge of producing sound. By being struck with a pick, they are able to produce various sounds and variations of chords in a cuatro. Puente (bridge): The function of the bridge is to be able to maintain the strings in the position they are supposed to be in. In the bridge there is a cejuela, which aids in this task as well. Caja armónica (harmonic box): This is the overall body of the cuatro. It helps modify the sound produced and helps spread it to the surrounding air or environment. Several sizes of the instrument exist, including a cuatro soprano, cuatro alto, cuatro tradicional (the standard instrument, also called cuatro tenor), and cuatro bajo (bass): All have 10 strings and are tuned in fourths. There is also a cuatro lírico (lyrical cuatro), which is about the size of the tenor, but has a deep jellybean-shaped body; a cuatro sonero, which has 15 strings in 5 courses of 3 strings each; and a seis, which is a cuatro tradicional with an added two-string course (usually a lower course), giving it a total of 12 strings in 6 courses. The Puerto Rican Cuatro is played with a pick, and the cuatrista will strike downwards on the string with the pick in order to generate