These 3D objects are created with the software of cubify. This is freely available on the website of them. Precisely create an account and choose the correct settings.
After some time, you can download the STL file and send to your 3D printer. The settings on the printer do not matter much. I leave them at default and the result is pretty good.
Link to the site of cubify: http://cubify.com/en/Store/Crafternoons
G-code fot the tealight attached.