I decided to branch out and try designing something for a full color powder printer. The STL really doesn't do it justice; if you have Windows 8.1 (or 10), you can open the 3MF with 3D Builder, which I work on.
I used NASA images: the Blue Marble for the earth, and the Hubble Deep Field for the knot. The earth is forever captured, but can roll around a knot-shaped orbit. See my video of the finished print.
One of the cool features we added to 3D Builder is "Buy Print", which allows you to make things in materials we can't manage at home. I printed this in Colorstone for $172 (I know, not as cheap as we'd like, but pretty good for a 6 inch wide piece).