     case 2: self = .half
     case 4: self = .quarter
     case 8: self = .eighth
-    case 16: self = .sixtenth
+    case 16: self = .sixteenth
     case 32: self = .thirtysecond
     case 64: self = .sixtyfourth
     default: return nil


extension NoteType: CustomStringConvertible {

  public var description: String {
    switch self {
    case .c: return "C"


/// Defines the duration of a note beatwise.
public struct NoteValue {
  /// Type that represents the duration of note.
  public var type: NoteValueType
  /// Modifier for `NoteType` that modifies the duration.
  public var modifier: NoteModifier

  /// Initilize the NoteValue with its type and optional modifier.
  ///
  /// - Parameters:
  ///   - type: Type of note value that represents note duration.
  ///   - modifier: Modifier of note value. Defaults `default`.
  public init(type: NoteValueType, modifier: NoteModifier = .default) {
    self.type = type
    self.modifier = modifier
