The toddaid is one of the 24 codified Welsh meters. This particular poem form consists of uneven couplets with lines of ten and nine syllables, featuring unusual rhyme schemes that utilize a technique called gair cyrch, ultimately resulting in staggered rhymes that feel exotic to English readers and writers.
The viator is a refrain-based poem type created by the Canadian poet Robin Skelton. It uses a refrain on the first line that becomes the second line of the second stanza, the third line of the third, and so on. The poem ends on the refrain, such that the number of lines per verse and number of verses per poem is equal.
The Than-Bauk is a Burmese tercet utilizing climbing rhyme. It consists of three tetrasyllabic lines with a single rhyme that starts on the last syllable of the first line, then on the third syllable of the second line, and finally on the second syllable of the last line. Than-Bauks are usually witty or humorous.
The trimeric is a product of the digital age and can be traced back to Dr. Charles A. Stone (which seems to be a pseudonym). It’s a short poem with just thirteen lines in a 4/3/3/3 pattern. Most of the lines in the initial quatrain become refrains in the tercets, with only the first line of the poem being unrepeated.
The trenta-sei is a fairly young poetic form from 20th-century poet John Ciardi. It consists of six heroic sestets (verses featuring both a Sicilian quatrain and heroic couplet). It also utilizes cascading refrains that are all established in the first verse. This form is unusually complex for its region and era.
The stornello is an Italian verse form dating back to at least the 15th century. The most common modern interpretations list it as a tercet form in which all three lines rhyme, with hendecasyllabic lines. There are other interpretations of the form from older time periods, including a couplet form still seen in Sicily today.
The somonka is a type of Japanese poem that actually consists of two shorter poems called tanka, a brief 31-syllable form, with somonka usually being exchanged by lovers or between two poets. Generally speaking, the first tanka is a love poem to the second person and the second tanka is the lover’s response.