On a lightly floured surface, roll out the first portion of dough with a rolling pin as thinly as possible into a (more or less) rectangle, approximately 2 millimeters thick. Dust the surface of the dough with flour and roll the dough it up into a loose log. (The flour will prevent the dough from sticking to itself as you roll.) With a sharp knife, slice the log into ¼-inch wide pieces. Unroll the noodles, sprinkle on flour and toss them all together into a pile. Repeat with the next portion of dough.