Historical clue formulations

• Common viper — 2021-09-19
• Total-itarian? — 2021-07-11
• Snake that's good with numbers? — 2019-06-13
• Summer — 2018-08-18
• Only poisonous snake in Britain — 2018-03-24
• Puff ___ (snake) — 2017-09-25
• Viperidae family member — 2017-09-02
• Member of the genus Vipera — 2016-10-09
• Puff ___ (snake) — 2016-07-25
• Puff ___ — 2016-03-22
• Viperidae family member — 2016-01-14
• Math columnist? — 2015-11-20
• Deadly viper — 2015-01-04
• One summing things up — 2014-07-13
• Hognose snake — 2013-11-09
• Small viper — 2011-05-16
• Abacus user — 2009-11-15
• Abacus, e.g. — 2009-04-05
• Abacus user — 2008-12-24
• Abacus user — 2006-12-12
• Summer — 2006-07-20
• Abacus wielder — 2005-12-07
• Viper — 2005-08-30
• Puff ___ — 2004-12-26
• Viper — 2003-08-10
• One working on a column — 2002-07-07
• Office machine — 2002-06-21
• Venomous snake — 2002-06-17
• Relative of a rattlesnake — 2002-04-28
• One working on a column? — 2001-11-03
• Figurehead? — 2001-09-22
• Summer — 2000-11-01
• Viper — 2000-05-17
• One who does 23-Across — 2000-03-24
• Viper — 2000-01-31
• Puff snake — 1999-03-22
• Viper — 1998-06-15
• Cousin of 42-Across — 1998-01-06
• Viper — 1997-09-29
• European viper — 1997-06-04
• Milk snake — 1997-05-10
• Calculating snake? — 1995-12-26