TETR
| Date | Clue |
|---|---|
| 2012-12-04 | Four: Prefix |
| 2010-10-15 | Half of oct- |
| 2009-08-12 | Numerical prefix with oxide |
| 2009-08-10 | Four: Prefix |
| 2008-06-29 | Four: Prefix |
| 2004-10-31 | Having four parts: Prefix |
| 2002-12-26 | Four: Prefix |
| 1997-05-25 | Fourfront? |
| 1994-06-19 | Four: Prefix |