Final answer:
The first building block of bound verse's metrical pattern is a foot consisting of two or three syllables in a rhythmic unit.
Step-by-step explanation:
The first building block of bound verse's metrical pattern is a foot, which consists of two or three syllables in a rhythmic unit. The iamb and trochee are two-syllable feet, with the iamb having a rising rhythm and the trochee having a falling rhythm. The spondee is another two-syllable foot with two equally stressed beats. The anapest and dactyl are three-syllable feet that have rising and falling rhythms, respectively.