Premise: Mandolin . It commonly has four courses of doubled metal strings tuned in unison ( 8 strings ) , although five ( 10 strings ) and six ( 12 strings ) course versions also exist . The round-back has a deep bottom , constructed of strips of wood , glued together into a bowl . Other mandolin varieties differ primarily in the number of strings and include four-string models ( tuned in fifths ) such as the Brescian and Cremonese , six-string types ( tuned in fourths ) such as the Milanese , Lombard and the Sicilian and 6 course instruments of 12 strings ( two strings per course ) such as the Genoese . There has also been a twelve-string ( three strings per course ) type and an instrument with sixteen-strings ( four strings per course ) .
Hypothesis: The mandolin has more than one style.
Label: ENTAILMENT