     case .half: return 2
     case .quarter: return 4
     case .eighth: return 8
-    case .sixtenth: return 16
+    case .sixteenth: return 16
     case .thirtysecond: return 32
     case .sixtyfourth: return 64
     }


extension ChordType: CustomStringConvertible {

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


extension NoteType: CustomStringConvertible {

  /// Converts `NoteType` to string with its name.
  public var description: String {
    switch self {
    case .c: return "C"
