Ambigrams are lettering (usually a word or words) drawn in such a way that it can be interpreted in more than one way. The type I do most often are drawn so that they read the same if turned upside down, though reflections and other symmetries can also be done.
(Spring 2001) Rotation, simple 1 letter to 1 letter mapping.
(August 2001) Rotation, 'S' to 'd' is a little dodgy, but the rest works well.
(August 2001) Rotation, my email address. 'm' to 'rd' and the 'edu' are tricky, but you expect things to go wrong in an ambigram this long.
(May 2001) Rotation/translation tesselation, design for a T-shirt for the Oxford University Juggling Club.
(May 2001) Rotation/translation tesselation, design for the British Crystallographic Association.
(October 2001) Rotation, Friend at Stanford.
(October 2001) Rotation, Friend at Stanford and ex-boyfriend.
(October 2001) Rotation, Me!
(November 2001) Rotation + colour inversion, Inspired by a design on Greg's webpage (friend from Oxford).
(November 2001) Rotation, Me! (again)
(November 2001) Rotations, Thanksgiving place markers.
(December 2001) Rotation, Friend at Stanford.
(January 2002) Rotation. Scott Kim's and John Langdon's ambigrams on this are very similar to each other, but the natural way for me to approach it turns out quite different from theirs.
(October 2002) Rotation. This one is both an ambigram and a autologlyph. It's unfortunate that I
had to cheat with the first 'y', although at least it is recognisable as a reflected 'y' as opposed to some other letter. Maybe given the context I get a bit more leeway?
(January 2003) Rotation. My other email address. Works pretty well throughout. I've used the 'ma' to 'an' trick somewhere before
but I can't remember where.
(May 2003) Rotation. The names are of a cousin of mine and his wife, this was my wedding present for them.
(October 2003) Reflection. For putting on glass doors. Inspired by a post to rec.puzzles by Kevin Stone.
(Dec 2003) Rotation. The names are of a friend in the math dept, and his wife (who is in the Berkeley math dept) this was my wedding present for them.