pulse is the regular occurrence of rhythm in time, unemphasized, one after another-- [clapping] undivided. in many instances, we want to organize that pulse. in western music, we'll use an accent on every two. for example, one, two, one, two, one, two. if you watch a marching band, you'll probably see a lot of duple time or time divided by twos or fours. if you watch the way they move, the way they step, it's often divided-- one, two, one two, one. if you watch somebody dancing to a waltz, you'll see the emphasis of their bodies moving on the first beat of every three-- one, two, three. one, two, three. and the choreography of their movement corresponds to that emphasis in time. pulse is also something that people perceive as an audience not just the musicians using accents to organize time. when you listen to music, you feel music, and you start to dance. you can see it at a large crowd of people at a concert, and everybody seems to be moving together. the rhythm is sort of a glue that holds the band together. it keeps everybody playing in time, as they say. and it keeps everybody thinki