Historical clue formulations

• Two times quadri- — 2022-02-15
• Twice tetra- — 2021-10-25
• Half of hexadeca- — 2021-08-20
• Multiple of tetra- — 2021-01-31
• Prefix with -gon — 2020-06-21
• Numerical prefix — 2018-11-28
• Numerical prefix — 2018-10-12
• Eight: Prefix — 2018-10-07
• Geometric prefix — 2018-09-02
• Twice tetra- — 2018-07-15
• Numerical prefix — 2018-06-03
• Twice tetra- — 2018-05-31
• Numerical prefix — 2018-05-13
• Numerical prefix — 2016-10-30
• Numerical prefix — 2016-01-31
• Twice tetra- — 2014-09-03
• Twice tetra- — 2014-04-27
• Numerical prefix — 2013-10-17
• Twice tetra- — 2013-09-08
• Numerical prefix — 2013-02-02
• Prefix with -gon — 2011-10-16
• Eight: Prefix — 2011-07-18
• Numerical prefix — 2011-07-10
• Two times tetra- — 2011-03-29
• Numerical prefix — 2011-01-02
• Prefix with -valent — 2010-06-26
• Quadri- times two — 2010-04-12
• Tetra- doubled — 2010-02-16
• Eight: Prefix — 2009-09-14
• Eight: Prefix — 2009-06-21
• Eight: Prefix — 2009-01-20
• Prefix with -gon — 2009-01-14
• Numerical prefix — 2008-11-09
• Numerical prefix — 2008-05-11
• Prefix with -hedron — 2007-09-21
• Prefix with -gon — 2007-07-11
• Eight: Prefix — 2007-05-15
• Numerical prefix — 2005-09-23
• Eight: Prefix — 2004-02-24
• Prefix with meter — 2003-12-25
• Prefix with -gon — 2003-08-13
• Prefix with -hedron — 2001-12-16
• Twice tetra- — 1999-06-30
• Penta plus three — 1999-01-31
• Numerical prefix — 1999-01-10
• Prefix with -gon — 1998-07-01
• Septi- plus one — 1998-05-20
• Prefix with -hedron — 1997-04-09
• Numerical prefix — 1995-11-23
• Eight: Prefix — 1995-04-04