to create optical materials with very unusual effective medium parameters. Engineering arbitrary values for the effective permittivity $\epsilon$ and permeability $\mu$ would allow new forms of light control based on achieving negative index materials [@Veselago68; @Pendry00; @Pendry01], or transformation optics media [@Pendry06] that arbitrarily reroute light through space. In order to reach such control over $\epsilon$ and $\mu$, many metamaterial building nanoblocks have previously been identified as having an electric and magnetic response to incident light, including split ring resonators (SRRs) [@Smith00; @Enkrich05; @Rockstuhl06; @Klein06; @Sersic09; @Lahiri10], rod-pairs [@Shalaev05], cut-wire pairs [@Dolling05], fishnet structures [@Dolling06; @Dolling07; @Valentine08] and coaxial waveguides [@Waele10]. In many instances, the nanoscatterers are not only interesting as building blocks in subwavelength lattices of designed $\epsilon$ and $\mu$. The building blocks are in fact very strong scatterers with large cross sections [@Husnik08; @Rockstuhl06b; @Corrigan08; @Pors10], comparable to the large cross sections of plasmonic structures. Therefore, metamaterial building blocks are excellently suited to construct magnetic antennas, array waveguides and gratings in which electric and magnetic dipoles couple and form cooperative excitations, in analogy to the functionality imparted by plasmon hybridization [@NordlanderScience]. Experiments outside the domain of effective media have appeared only recently. These experiments include experiments by Husnik 