Historical clue formulations

• Celestial circles — 2019-08-07
• Symbols of innocence — 2018-09-28
• Head bands? — 2017-04-30
• Headbands? — 2013-05-25
• Features in many Fra Angelico paintings — 2010-08-28
• Headbands? — 2001-12-11
• Lunar phenomena — 1997-06-29
• Overhead figures? — 1996-12-01
• Angelic headwear — 1996-01-10
• Nimbi — 1995-06-18