A friend sent me a link to Detextify2:
What is this?
Anyone who works with LaTeX knows how time-consuming it can be to find a symbol in symbols-a4.pdf that you just can't memorize. Detexify is an attempt to simplify this search.
How does it work?
Just draw the symbol you are looking for into the square area above and look what happens!
My symbol isn't found!
The symbol may not be trained enough or it is not yet in the list of supported symbols. In the first case you can do the training yourself. In the second case just drop me a line (danishkirel[[[at]]]gmail.com)!
I like this. How can I help?
You could spare some time training Detexify. You could also look at the source on GitHub and if you want to contribute you're welcome.
Who created Detexify?
Philipp KÃ¼hl had the initial idea and Daniel Kirsch made it happen.
Pretty cool. One step closer to the day when I write an equation on a piece of paper and the LaTeX just automagically appears for this at equation.
Except right now it seems to need training for everything.
I refer you to a quaint aphorism about walking, running, and the proper precedence thereof...
You might want to take a look at the "freehand formula entry system", which turns strokes into characters, and then tries to parse them into reasonable mathematical expressions.
It definitely could use a lot of overhauls, but it does more or less work.