The ship is more cool with a skull and crossbones. Load both files into Cura, right click one, and choose dual extrusion merge. If you print too small, the skull and crossbones isn't clear. I enlarged it so that it will show up clearly at smaller sizes than it otherwise would have. Don't print the splitting tool. That is just here so you can see how I made this. If you want to know how to draw something like this, read the instructions that I've included here. Based this on thing 726107 -- which is cool, but I had to entirely redraw it to get the dual extrusion to work. Apparently, you can't just chop up an stl file and prepare something for dual extrusion properly. How did I prepare this for dual extrusion? Another person asked how this is made, as there isn't much content with dual extrusion available for printing. If you have a dual extruder, it seems super cool, but It is like having a 4k tv, and nothing to watch in 4k. First, take a look at this video: https://www.youtube.com/watch?v=_1giymE4iXI It tells you the basics of how to prepare a model for dual extrusion merge. However, it doesn't tell you that you can't do this if all of the parts of your splitting tool aren't touching. This is because you apparently can't merge parts into one unit if they are not touching, and grouping doesn't appear to work. I found that I had to connect all of the parts of my splitting tool to get the dual extrusion merge to work. I will add a picture and stl file so you can see what the splitting tool looked like before I applied it to the model. Second, when drawing in 123d design, save your work often. I had it crash and go away, losing my work, several times. To make this as dual extrusion, I had to entirely redraw the boat and sails in 123d Design. (This is the first thing I've drawn.) I then made a copy of the sails, and moved them 80mm to one side. This left the ship and sails together, and gave me a separated copy of the sails. I used the merge function to merge the original ship and sails into one piece. Now I had a ship with sails as one piece, and some sails 80mm to one side. Getting the three stacks of sails to merge was tricky because they are not connected to each other. I connected them together with a small cylinder, and then merged the sails into one piece. I drew and added the skull and crossbones in the same fashion. None of the connecting rods can intersect with the ship model that will be retained or the split will fail. You can see that none of the red cylinders are touching the blue ship. Now I moved the sails and skull and crossbones assembly (splitting tool) back 80mm back the other way and use the split function. After performing the split function, the splitting tool can be deleted. While both parts are aligned with each other, Hide the ship, export stl, reveal the ship, hide the sails, and export stl. Now you have two pieces that are suitable for dual extrusion printing.