In a blog post from February the developers wrote:
I’m making a new layout library, called Packery. It is awesome because it resolves two of biggest and oldest issues with Masonry or Isotope.
It’s been in development for the past several months, and it still has a ways to go until a full public release. Here’s a sneak peek.
I am really looking forward to playing around with Packery as I have fallen in love with Isotope in the past few months and Packery looks to be a lot more robust.
From a responsive design point of view a tool like this really makes sense and can add both dynamic layouts based on width or height, control moving or expanding containers easily and will even handles multitouch inputs from touch screens.