Historical clue formulations

• Geom. figure — 2019-03-28
• Geom. shape — 2016-04-10
• Four-sided fig. — 2015-10-07
• Geom. shape — 2014-09-24
• Geom. figure — 2011-10-30
• Like most city blocks: Abbr. — 2010-10-03
• Geom. figure — 2007-12-28
• Prefix with angular — 2006-01-01
• Mathematical fig. — 2005-08-14
• Prefix with angular — 2003-06-08
• Geom. figure — 2003-05-23
• Geom. shape — 2001-04-07
• Four-sided fig. — 2000-06-08
• Geometric fig. — 1999-03-03
• Prefix with angle — 1997-12-26
• Geom. shape — 1997-12-24
• Quadrilateral fig. — 1995-05-08
• Right: Prefix — 1995-01-31
• Straight prefix — 1994-07-01