The first one I remember designing was something like this, where the word "backward" looks
the same when you hold it up to a mirror:
Here's another with mirror-sameness:
Of course, you can do the word "mirror" itself like this:
Rather than being the same in a mirror, this one reads the same if you turn it upside down:
I made a label for the honey bottle that reads correctly even when you turn it
over while using it:
Here is the name OHIO, which is spelled correctly even when given a quarter turn:
I made this version of my business name, so it can be put on the window and look the same
whether you are inside or out:
Some ambigrams say one thing when viewed one way and another when viewed upside down.
This design could be put on a magnet for the dishwasher and turned to indicate whether the dishes are clean or dirty:
Click HERE for a tongue-in-cheek application of the same principle.
This was intended to be a prototype of a metal sculpture of my first name; when reflected in
water with me posing so that the middle zigzags are obscured, my last name appears: