Mm, hybrid poetical forms. The limeronnet: 7 couplets, alternately long and short limerick metre, with the long couplets all using the same rhyme. The sonnaiku: 14 syllables in 4 lines with ABBA rhyme. The limerestina: a cycle of five limericks plus a final couplet following rules too complicated to work out. The villanellerick, the Petrarchan tercet, the epic cinquain, ...