It uses Masonry, from the same author as Isotope. Difference between those two is that Isotope uses GPU accelerated CSS animations. Sadly there are quite a few

It uses Masonry, from the same author as Isotope. Difference between those two is that Isotope uses GPU accelerated CSS animations. Sadly there are quite a few bugs when you combine CSS animations with flash (for example on the iPad), videos won't render on the proper position. Therefore I had to stay with masonry. Please let me know if someone is aware of a workaround. (Example of the bug: http://jsfiddle.net/desandro/t3Cmy/ http://jsfiddle.net/desandro/t3Cmy/)