If you come across a symbol you've never seen before, or you want to look up the unicode for a certain symbol, it may be a small challenge to search for it if you're not entirely sure of its name. Mausr lets you draw the symbol instead, then identifies it based on your drawing. The open source web app allows you to draw with your mouse or trackpad to look up certain symbols. You don't have to draw in a single stroke -- it refreshes as you go. Once you submit your drawing, Mausr gives you several options of what the symbol could be. Its developer explains:
Have you ever wanted to easily find any unicode symbol like →, ×, ≠, ℝ, or »...Just sketch the symbol you are looking for and half a second later you have it ready for copy-paste along with some useful infromation [sic].
Mausr stands for Marek's Unicode Symbols Recognizer and I created it because I was frustrated by googling unicode symbols around. First it was only small C# program but then I realised that it can be actually usefull [sic] for everybody. So I extended the library with simple web interface and after few weeks the first version was published
It includes over 100 symbols in its database and you can check it out for yourself at the link below.