The main interest in this technique is that's an application of an
abstract principle that could be applied elsewhere: the "crossing the
t's" manipulation technique. It's a new interface idiom to add to the
The author's of the fold'n'drop explain the general principles of this
technique - called the "Law of crossing":
There's also the related "Law of Steering", moving the cursor through
a path without touching the borders - an example of this would be
trying to move the cursor from a menu to an unfolding submenu.
These authors have studied these processes in quantitative way,
inspired by the famous Fitt's Law that describes and measures
point'n'click behavior. It seems that these three "Laws of Action"
will be a valuable tool for researching user interfaces in a
scientific way, and probably will be the basis for new interaction
techniques like this fold'n'drop.
I've found this curious experiment that shows a click-less interface,
entirely based on pointing, crossing and steering. It has some
interesting techniques that could be applied to eye-tracking and
tablet devices. Give it a try: