the masnavi or mathnawi,
Couplet (or two-line) form…
…but with the qualifier that each “line” is actually a “half-line” and that they rhyme horizontally
Each line is 10 or 11 syllables long (I believe it’s supposed to be consistent within the poem, so pick a number and stick with it)
Rhyme scheme is aa/bb/cc/dd and so on
No line length restrictions
Many examples of masnavi are very long poems. One of the more popular examples is Rumi’s Masnavi-ye-Ma’navi, which is a long spiritual or mystical poem.
Thankyou to the Writers Digest for this information.