| 2025-03-17 | Face shapes |
| 2025-03-07 | Slices of hard-boiled eggs, for instance |
| 2024-07-15 | NASCAR circuits, geometrically |
| 2024-03-12 | Racetrack shapes |
| 2022-08-18 | Some tracks |
| 2022-05-19 | Cricket fields and badminton racket heads, for two |
| 2021-09-04 | Cricket fields, e.g. |
| 2019-08-18 | 0 0 0 |
| 2015-07-18 | Ford and Kia logos |
| 2015-05-04 | Toilet seats, geometrically |
| 2014-12-28 | Eggs, e.g. |
| 2014-06-07 | What many racers race on |
| 2012-04-10 | Track shapes |
| 2010-12-08 | Most toilet seats |
| 2010-07-14 | Cameo shapes |
| 2010-04-26 | Racetrack shapes |
| 2010-03-30 | Egg shapes |
| 2009-03-31 | Cameo shapes |
| 2008-10-23 | Tracks |
| 2008-01-15 | Racetracks |
| 2007-01-22 | Flattened circles |
| 2006-12-03 | Nascar circuits |
| 2006-03-18 | Toilet seats, e.g. |
| 2006-01-23 | Picture frames lacking corners |
| 2005-04-07 | Most cricket grounds |
| 2003-07-12 | Spaces for races |
| 2003-05-02 | Racing paths |
| 2000-07-30 | Tracks |
| 1998-05-12 | Race tracks |
| 1997-09-07 | Tracks |
| 1997-07-19 | Some windows |
| 1997-07-13 | Some picture frames |
| 1997-06-29 | Tracks |
| 1997-01-19 | Places for races |
| 1996-07-28 | Amphitheaters |
| 1995-05-25 | Round figures |
| 1994-11-04 | Cartouches |
| 1994-07-18 | Race tracks |