In actual practice this pattern is complicated by the subdivision of beats into even or dotted two-syllable pairs and the addition of prefix syllables which occupy the rest at the end of the previous line; each line may therefore include eleven or twelve actual syllables. In the modern form, there are sudden tempo changes from the slow introduction to the faster main section of the song. Almost every contemporary "mor lam" song features the following bassline rhythm, which is often ornamented melodically or rhythmically, such as by dividing the crotchets into quavers: