▁a ▁tone ▁cluster , ▁listen ers ▁can ▁hear ▁the ▁twelve - t one ▁ch ords ▁as ▁a ▁symmet r ically ▁spac ed ▁ch ord . ▁( Ro ig - Fran coli ▁ 2 0 0 8 , ▁ 2 8 7 – 9 1 ) ▁ ▁S ources ▁▁▁ ▁Category : Com pos itions ▁by ▁Wit old ▁L utos ław ski ▁Category : 1 9 6 1 ▁compos itions ▁Category : Com pos itions ▁for ▁chamber ▁or chestra <0x0A> </s> ▁Bro d owo ▁ ▁is ▁a ▁village ▁in ▁the ▁administrative ▁district ▁of ▁G mina ▁Ś w ier cze , ▁within ▁Pu ł t usk ▁County , ▁Mas ov ian ▁Vo iv odes hip , ▁in ▁east - central ▁Poland . ▁It ▁lies ▁approximately ▁ ▁east ▁of ▁Ś w ier cze , ▁ ▁west ▁of ▁Pu ł t usk , ▁and ▁ ▁north ▁of ▁Wars aw . ▁ ▁References ▁ ▁Bro d owo <0x0A> </s> ▁Joy ▁Morris ▁( born ▁ 1 9 7 0 ) ▁is ▁a ▁Canadian ▁math ematic ian ▁whose ▁research ▁involves ▁group ▁theory , ▁graph ▁theory , ▁and ▁the ▁connections ▁between ▁the ▁two ▁through ▁C ay ley ▁graphs . ▁She ▁is ▁also ▁interested ▁in ▁mathematics ▁education , ▁is ▁the ▁author ▁of ▁two ▁open - access ▁under grad uate ▁mathematics ▁text books , ▁and ▁over se es ▁a ▁program ▁in ▁which ▁university ▁mathematics ▁education ▁students ▁provide ▁a ▁drop - in ▁mathematics ▁t utor ing ▁service ▁for ▁parents ▁of ▁middle ▁school ▁students . ▁She ▁is ▁a ▁professor ▁of ▁mathematics ▁at ▁the ▁University ▁of