Historical clue formulations

• Rhyme scheme ending a villanelle — 2017-07-23
• Rhyme scheme in the last verse of a villanelle — 2016-10-18
• Certain quatrain rhyme scheme — 2015-09-16
• Rhyme pattern at the end of a villanelle — 2014-05-03
• Common quatrain form — 2013-11-17
• Simple quatrain form — 2013-10-16
• Quatrain rhyme scheme — 2013-08-04
• Simple rhyme scheme — 2011-03-14
• Simple quatrain form — 2009-03-11
• Quatrain form — 2008-08-07
• Simple rhyme scheme — 2008-04-15
• Simple rhyme scheme — 2006-12-06