One of the items that came from the Fortus 3D printer this week (Feb 2013) was a 5" x 5" model of a 6mm x 6mm blood vessel in the human eye. Notice that you can now use red, as shown below, and black plastic in the Fortus printer. A U.S. quarter is 24.3mm wide.
Another vessel was printed 3/5/13, as shown below.
Research done by Li Zhang, with supervision by Milan Sonka and Michael Abramoff.