  We propose a mathematical model of DNA self-assembly using 2D tiles to form
3D nanostructures. This is the first work to combine studies in self-assembly
and nanotechnology in 3D, just as Rothemund and Winfree did in the 2D case. Our
model is a more precise superset of their Tile Assembly Model that facilitates
building scalable 3D molecules. Under our model, we present algorithms to build
a hollow cube, which is intuitively one of the simplest 3D structures to
construct. We also introduce five basic measures of complexity to analyze these
algorithms. Our model and algorithmic techniques are applicable to more complex
2D and 3D nanostructures.
