You can search Google for Upside Down Text or use the link below
And as far as code, if you mean HTML code there are unicode conversions for each of the upside down characters. These can be found in the second link below or by a google search for upside down text unicode.
They're OIXZH
The Upside down T symbol indicates perpendicular lines.
If you have one like mine, all you have to do is turn it 90 degrees to the right, push down, and then change the code while holding it down.
In mathematics an upside down triangle corresponds to the gradient operator and is sometimes called "del". The Greek symbol of an upside down triangle is called "Nabla".
For All.
an upside down question mark = ALT + 168
SIS
this \
They are also letters upside down: y n u o s x and z Comment: Don't think that's it. Y is not an upside-down h. If this is it, c and l are missing from the set, and you'd have to allow p as an upside-down b. Besides, the answer could involve the capital letters instead.
Search google for "upside down text" and then you'll find websites where you can turn letters around!
There is more than just 1. C, D, O, S, and B are all curved letters that are the same upside down.
There is no hidden code here, it just means he wasn't paying attention and could have been in a rush when he put the stamps on the envelope.
SOS
SWIMS (:
If you mean the 1950s-1960s peace sign that looked kinda like a circle with an upside down "Y" inside it; it was two letters in Naval Semaphore Code overlapped. Those letters were N and D which stood for Nuclear Disarmament.
The upside down version: SWIMS The right side up version: SWIMS This is the word that is 5 letters in capitals the same turned upside down :)) Hope that helps all you smart kids out there <3
Yes, you can flip it upside down to get a d, you can flip it backwards to get a p and u can flip it upside down and backwards to get a b