Hemistich markers: The ends of the hemistichs are marked and contrasted by an obligatory stress: a specific syllable position near the end of each hemistich must be filled by a stressed syllable, and this position typically differs between the first and second hemistich, so that they are audibly distinct.
Marker reinforcement: Often the syllables immediately before or after the obligatory stresses are obligatorily unstressed to further emphasize the stress.