Source Files

The source files included in the original artwork are provided as Scalable Vector Graphics (SVG). SVG is a family of specifications of XML-based file format for describing two-dimensional vector graphics, both static and dynamic (interactive or animated).

Being XML files, SVG images can be edited with any text editor, but specialized SVG-based drawing programs are also available. I used Inkscape, but there are many more free editors available.

If you're using Ubuntu, click here to install Inkscape. For other operating systems, visit the official website.

Source: Wikipedia.