(Bottom) Schematic of the tight-binding model realized by Aidelsburger et al. in their cold-atom experiment . Red and blue spheres (labeled by A and B) denote sites. Arrows in the middle of plaquettes show the direction of the effective magnetic field. (Top) Schematic of the optical lattice potential with period two superlattice in the x direction used in the experiment. The large detuning between the red sites and blue sites prevents tunneling in the x direction. Two external lasers are introduced, whose detuning coincides with the energy mismatch, restoring tunneling. Phases from these lasers lead to the staggered effective magnetic field appearing in the tight-binding model.