Historical clue formulations

• Sink — 2018-07-28
• Derive (from) — 2014-12-13
• Be patronizing — 2013-12-05
• Rappel down — 2008-05-18
• Climb down — 2001-09-17
• Drop — 2001-03-30
• Fall — 1998-10-31
• Prepare to land — 1998-02-01