Musical instruments that start with the letter I include the igil, ipu, Irish uillean, Irish bouzouki, ichigenkin, inci, iya, itotele and istarski mih. The instruments originate from countries ranging from Cuba and Ireland to Croatia, Japan and the Philippines.
Bessel's functions are often used in acoustics for describing circular membranes behaviour (exploited by most of the musical instruments). They are the solutions of the wave equations using polar coordinates. Set the properties of the membrane Bessel's functions describe the vibrational modes of the membrane.
Because the tassel would still be turned to the right during the handshake photograph, it would be on the opposite side of the photographer, which is desired. Graduates could move their tassels individually while departing stage, or do so in unison after all degrees have been conferred.