Text this: Mutually unbiased bases for the rotor degree of freedom

  _____      ___      _  __   _    _    _____    
 / ____||   / _ \\   | |/ // | || | || |  __ \\  
/ //---`'  / //\ \\  | ' //  | || | || | |  \ || 
\ \\___   |  ___  || | . \\  | \\_/ || | |__/ || 
 \_____|| |_||  |_|| |_|\_\\  \____//  |_____//  
  `----`  `-`   `-`  `-` --`   `---`    -----`