what does an A note look like?

An A note is a sound.

Now if you are asking what the notation for an A note is

A

Now there are many other notations: OCR, Braille, sheet notation, at least 15 current ways to write music notation.

http://en.wikipedia.org/wiki/Musical_notation

Notice here
http://datadragon.com/education/reading/clefs.shtml
how many A's are listed.