| 2021-02-14 | Kind of symmetry |
| 2016-12-01 | Like the rotation of the earth |
| 2012-06-14 | Kind of skeleton |
| 2011-05-18 | Like some symmetry |
| 2010-08-16 | Like some symmetry |
| 2008-04-26 | Kind of skeleton or symmetry |
| 2005-08-13 | Kind of skeleton |
| 2004-08-01 | Having a line of symmetry |
| 2004-06-21 | Like some symmetry |
| 2004-06-06 | Like some rotations |
| 2003-05-07 | Like some symmetry |
| 2002-03-23 | Kind of skeleton |
| 1999-09-28 | Variety of symmetry |
| 1999-06-25 | Kind of skeleton |
| 1999-05-20 | Perpendicular to radial |
| 1998-06-30 | About the line of rotation |
| 1996-10-12 | Kind of symmetry |
| 1995-06-11 | _____-flow turbine |
| 1995-04-04 | Having a line of rotation |
| 1994-02-23 | The A in "CAT scan" |