SVG Lava Lamp

The blog post about how is it made: http://codepen.io/chrisgannon/post/how-to-make-an-svg-lava-l...

I had no idea SVG filters were powerful enough to do things like that cool blobbing-together effect... in 3 lines of actual filter! (lines 8-10 of the html)

(I haven't actually followed along with building my own, nor do I know SVG, so apologies and let me know if that is not the bit which is doing the blobbing together)