This is neat. It doesn't seem to conserve volume. If you spread the blob "inward", all the fluid disappears and you get a tiny thin spot.

That's a general problem I often run into with simulations. When you get it in the opposite direction it can have some very amusing results (e.g. energy in a physical system continues to increase).

You can also make infinite paint by spinning a small circle, then cycling between larger and small circles! It seems it also converges to secondary colors over time if any other primary color is added. Very cool!

They explain why this happens in the article.