There is a recent post on the Omniglot blog that talks about ambigrams. I have read about them before and I have tried to make a few ambigrams but most of them are either hard to read or ugly (or both). I'm not at home but I tried to make a sketch of an ambigram of Omniglot with Paint just now. (Caution: It may cause damage to eyes)
And this is an ambigram of four. Luckily I put it on Facebook so I can post it now
I made it with SumoPaint
. It has a symmetry function, which is very good for making ambigrams.
Have you made any ambigrams before? (I'm sure there are a lot of people on here who make better ambigrams than me