Traditional playing styles use the right hand to pluck notes and the left hand to add ornamentation such as pitch slides and vibrato by pressing the strings to the left of the movable bridges. Modern styles use both hands to play on the right side of the strings. There are many techniques used to strike notes. One iconic sound is a tremolo produced by the right thumb rotating rapidly around the same note. Other guzheng techniques include harmonics ("Fanyin") where one plucks a string while tapping it at the same time, producing a note in a higher octave.