A method and apparatus for assembling microstructures onto a substrate through fluid transport. The microstructures being shaped blocks self-align into recessed regions located on a substrate such that the microstructure becomes integral with the substrate. The improved method includes a step of transferring the shaped blocks into a fluid to create a slurry. Such slurry is then dispensed evenly or circulated over the top surface of a substrate having recessed regions thereon. The microstructure via the shape and fluid tumbles onto the surface of the substrate, self-aligns, and engages into a recessed region.