| Date | Subject |
|---|---|
| May 14, 1991 | Optimal change and related trivia |
| May 16, 1991 | Optimal change and related trivia |
| January 8, 1992 | Noughts and crosses |
| September 23, 1994 | C puzzle |
| December 23, 1994 | Cutting up "nice" 3D objects |
| December 15, 1997 | How many points (9 different queens...) |
| August 15, 2005 | Bitwise palindromes |
| January 10, 2010 | Kurt Gödel PROVED that ALL math must be kept within certain parameters |