This is the Georgia Institute of Technology (GA Tech) logo that I printed for my favorite EE Professor Dr. John B. Peatman.

It was created starting with the GaTechYellowJacket.gif file that I downloaded from the Internet (because it was a nice 3 color logo). From this image I used GIMP http://www.gimp.org to create two black and white images (GaTechYellowJacket-Yellow.jpg and GaTechYellowJacket-Black.jpg) and then I uploaded these to the Shapeways and used their 2D to 3D tool http://www.shapeways.com/creator/2d_to_3d/ to create two STL files (GaTechYellowJacket-Yellow.stl and GaTechYellowJacket-Black.stl). These I then combined using the OpenSCAD http://www.openscad.org script (GaTechYellowJacket.scad) with a square (or round) backplate, then the yellow layer and finally the black layer on top.

This is then the different STL files: GaTechYellowJacket-Square-18x18.stl, GaTechYellowJacket-Round-18.stl, GaTechYellowJacket-Square.stl and GaTechYellowJacket-Round.stl. The one I printed for John as a present was the first one (GaTechYellowJacket-Square-18x18.stl).

Pick your desired STL image (from the four provided) and start printing with white filament. When it starts on the yellow layer pause the print to change to a bright yellow filament and then continue printing until you finally reach the black layer where you again pause the print and change to black filament and then continue printing until done.

I find it works easiest if I just cut the filament at the top of the extruder (flat cut) and then press the new filament (also with a flat cut) into the hole as it continues printing until the bearing and hobbed bolt have a firm grip on the new filament at which time you can let go.