Historical clue formulations

• Adobe, e.g. — 2015-03-11
• Building material in Oz — 2014-11-09
• Shade of red — 2013-04-20
• Symbol of thickness — 2009-05-03
• Building block — 2004-06-02
• Building block — 1995-06-20
• Third little pig's material — 1994-10-02