One popular ambigram theme is to make symbiotograms of opposites. Black and white, life and death, love and hate—these are some of the most commonly attempted couples I've seen. The latest ambigram I made fits very well into this category.
Zenith – Nadir, Inkscape, August 2010
It was somewhat inspired by the well known natural 'up/dn' pair. The zenith and nadir, the directions straight upwards and downwards from a given observation point, are in a very strict, mathematical sense each opposites. Naturally I had to add the arrow detail to the n/h glyph, to emphasize the opposing directions.
