Certain groupings of neumes were used to indicate repeating rhythms called rhythmic modes. Dances generally have a characteristic tempo and rhythmic pattern. His poems are known for their lyricism coupled with complex rhymes and rhythmic structures. His works are frequently noted for their rhythmic, optimistic, and lyrical nature. Tapping or slapping the body of his guitar added rhythmic accompaniment. Rap arose from musical experimentation with rhyming, rhythmic speech. This work therefore dealt with repetition and subtle rhythmic change. Most of the churches relied on hand clapping and foot stomping as rhythmic accompaniment. Synchronized firing of neurons also forms the basis of periodic motor commands for rhythmic movements. Christian's major influence was in the realm of rhythmic phrasing. Musicologist Leonard B. Meyer demonstrated how purely rhythmic and harmonic events can express human emotions. Previously Stravinsky had used series of notes without rhythmic or harmonic implications . They dance in the streets with wild costumes and masks accompanied by rhythmic music. These circuits are responsible for controlling motor instructions for rhythmic movements such as walking.. These numbers made use of typical Cuban rhythmic patterns.