Historical clue formulations

• Drone's sound — 2026-03-16
• Sound from fans — 2025-12-13
• Fan noise — 2024-10-14
• Sound from a fan — 2021-10-27
• Noise from a fan — 2021-03-11
• Sound made by helicopter rotors — 2021-01-18
• What helicopter rotors do — 2019-10-06
• What rotors do — 2019-09-05
• Blender sound — 2019-05-26
• Fan sound — 2018-06-22
• Fan sound — 2017-08-22
• Drone of a drone, say — 2016-09-29
• Blender sound — 2015-07-05
• Fan sound — 2011-11-23
• Fan sound — 2009-03-30
• Result of a quick revolution — 2006-03-24
• Fan sound — 2006-02-15
• Blender sound — 2004-02-29
• Fan sound — 2002-09-12
• Buzz — 2002-05-11
• Fan's sound — 2001-04-04
• Blender sound — 2001-01-28
• Fan sound — 2000-11-29
• Fan's production — 2000-07-14