Reliable and simple techniques for rapid assembly and patterning of colloid architectures advance the discovery and implementation of such nanomaterials. This work demonstrates rapid electrokinetic two-dimensional assembly of colloidal structures guided by the geometry of thin film heaters within a parallel-plate device. This system is designed to enable either independently addressable or massively parallel colloidal assembly. A combination of electrothermal hydrodynamics, particle-electrode, and particle-particle electrokinetic interactions governs their assembly. Concentration and patterning of structures are shown with 1.0 mu m polystyrene particles and sorting between 1.0 mu m and 2.0 mu m particles is demonstrated. (C) 2012 Elsevier Inc. All rights reserved.