Here is a tutorial for the Batman Shuriken!
1) Download Inkscape here for free.
2) Use the path tool and draw half of your path
3) Keep drawing!
4) MMkay, now edit the paths and curve it just how you like it.
5) Now clone and flip your path. Then select both paths and union them together.
6) There you go.
7) Add a fill and you are done.