Here is a re-creation of an object I modeled a few months ago. It's inspired by the sky disk of Nebra which is more than 3600 years old (Bronze Age). I used Gimp to create extract some black/masks from a photo (see gallery) and assembled everything with my 2d to 3d application "eXtrudy":
Extrudy_Nebra_Skydisk_2013_11_06_01_16_03.stl | 12.2MB |