The Sun Microsystems logo is one of the most famous (and my personal favorite) ambigram logos.

https://commons.wikimedia.org/wiki/File:SUN_microsystems_log...

Interestingly, rotational ambigrams can also occur naturally, e.g. “OHIO”: https://en.wikipedia.org/wiki/Ambigram#/media/File%3AAmbigra...

:-O

TIL or rather today I saw the letters there for the first time. Just thought it was S's all these years! Nice one