How to make a pure css triangle which has a white center

Question

I want to create an upward and downward facing arrow with css like the following: http://apps.eky.hk/css-triangle-generator/

However, instead of a solid color, I want to

Answer 1

Depending on how you're using it, you can make a triangle, with a border and even box shadow, without the triangle border hack, using CSS transform: rotate(). See my answer here: https://stackoverflow.com/a/8867645/918414