Physicists Invent A New Quantum Entanglement Derivative

Physicists developed a way to use entangled pairs of photons to determine qualities of an additional pair of photons. It seems to me something like determining a logical contrapositive state of quantum wavelets by determining the values of the initial bound pairs. The new trick is in making a relation between particles that don't exist at the same time. So can there be other logical relationships determined in such ways, and what would be the limits to structural construction complexity?

http://news.sciencemag.org/sciencenow/2013/05/physicists-create-quantum-link-b.html?ref=hp