Historical clue formulations

• Geometry suffix — 2024-03-29
• Ending with poly- — 2021-08-22
• Suffix with penta-, hexa-, hepta-, etc. — 2012-01-16
• Suffix for shapes — 2010-09-05
• Suffix with penta- — 2010-05-18
• Suffix with 19-Across — 2008-02-01
• Shape ender — 2006-10-21
• Geometry suffix — 2006-06-18
• Shape-indicating suffix — 2005-06-02
• Angled: Suffix — 2001-09-15
• Geometry ending — 2000-04-30
• Geometry suffix — 1999-10-26
• Geometric combining form — 1999-04-04
• Geometric suffix — 1998-05-23