The two-color option, for those who can, is laid out for a MakerBOT Replicator with two .stl files. Each will need to be “moved to platform” and “centered” to assure accurate registration relative to each other. Make a .gcode file of each and then (for us, after closing and re-opening a clean run of ReplicatorG) on the “Gcode” pull down, select “merge .stl for dual extrusion”. Pick one of your 2color .gcodes for left and the other for right, give the resultant merged dual .gcode a name and select “merge”.

The single-color option is all on one .stl file.

Enjoy!