Simplify the following text for a Grade 12 native English-speaking person.
Original: The variations differ sharply : a running line , a set of close harmonies , a march , and a polonaise ; the interludes are one of the first uses of bitonality ; William Schuman arranged this for orchestra in 1964 and again for symphonic band in 1968 .
Simplified: The variations differ sharply : a running line , a set of close harmonies , a march , a polonaise , and a ragtime allegro ; the interludes are one of the first uses of bitonality .