Provided are methods of preparing a plurality of extrusions, comprising (a) shrinking a transparent first thermoplastic material comprising a plurality of non-transparent marks, (b) lithographically transferring the pattern of the shrunk non-transparent marks to a layer of photoresist deposited on a second thermoplastic material, and (c) shrinking the second thermoplastic material, thereby generating a plurality of extrusions on the shrunk second thermoplastic material.