Historical clue formulations

• Tic-tac-toe marks — 2023-05-03
• Tic-tac-toe plays — 2018-02-23
• Playbook symbols ... or letters treated symbolically in this puzzle's Down answers — 2017-04-06
• Chalk talk symbols — 2015-04-25
• Playbook figures — 2011-06-05
• Football coaching figures — 2008-03-15
• Tic-tac-toe — 2004-02-20
• Love letters? — 2002-11-22
• Tic-tac-toe plays — 2001-07-01
• Tic-tac-toe plays — 2000-05-12