Pixar and Khan academy teamed up to educate public about math behind Pixar movies. You can read about the Pixar in a Box initiative at Brit Cruise's blog.
I am going to tell you how to use the site to create Vector graphics using Build you own shape demo at the Khan Academy site and Inkscape software.
Start making your own shpaes using the tool at Khan academy.
You will see a black box under the image including coordinates of vertices.
Click in the black box and do Ctrl-A to select the text. Ctrl-C to copy.
Now create a simple closed polygon in Inkscape. And save the file as SVG. Svg files are simple text files used to describe vector shapes. A vector polygon is just a collection of coordinates similar to one you just exported from Khan academy.
Here is what you see after you open the SVG file in a text editor.
Find the path. You can see the coordinates of the polygon you just draw as number pairs. I highlighted the numbers in yellow.
Delete the shape you draw in Inkscape:
Get rid of extra text by simple find and replace... Just coordinates X's and Y's...
Paste the numbers in place of old shape in inkscape file by a text editor.
Save and open the SVG in Inkscape.
Now you have access to all capabilities of Inkscape. I did some coloring, smoothing and additions.
That's it. You can download SVG here.