Historical clue formulations

• Swirling currents — 2026-01-11
• Goes down the drain, perhaps — 2024-08-17
• Swirling currents — 2020-09-28
• Moves like a whirlpool — 2016-11-15
• Swirls — 2015-12-10
• Fluid dynamics phenomena — 2009-07-24
• Swirls — 2008-01-24
• Whirlpools — 2006-11-05
• Whirlpools — 2005-01-23
• Whirls — 2003-10-25
• Whirling currents — 1999-09-07
• Vortexes — 1998-11-15
• Whirling currents — 1995-07-31
• Cantor and Murphy — 1995-06-28
• Swirls — 1994-02-04