Historical clue formulations

• Narrow groove — 2022-09-04
• Tiny groove — 2013-01-26
• Narrow groove — 2009-02-15
• Narrow groove — 2003-07-13
• Architectural flute — 1997-11-30
• Narrow furrow — 1997-07-16
• Narrow furrow — 1994-12-04
• Small groove — 1993-12-31