It's just like the original SpaceChem pin, but with internal sockets for 5mm Nd (neodymium) based spherical magnets! (eg. Buckyballs)
Since they're able to rotate freely, you can attach the Nd pin to any other magnets and it should behave itself. This includes pinning it to a shirt/uniform without piercing the fabric.
Additionally, the pause needed to insert the magnets is an excellent opportunity to add contrast by changing the filament to another color!
I intend to more fully document the process of inserting the magnets on another thing, but they're being published out-of-order because I wanted to post this remix less than 24 hours from the original. :)
2013-05-21: Fixed incorrect capitalization of "SpaceChem". Whoops!
REQUIREMENT: To insert magnets and perform the filament color-change as intended, you will need printer firmware that supports pause-at-z. I highly recommend Sailfish (if compatible): http://www.thingiverse.com/thing:32084
WARNING: Before attempting to insert magnets, test to see if they'll be attracted to your extruder's nozzle (eg. brass versus steel). It should be okay for them to be attracted to the extruder's gantry, as it should be far away enough to not lift them out of their sockets.
WARNING: After inserting the magnets, lightly push them into their holes (since they'll be clinging to the walls), and then visually inspect from the side to make sure they're completely below the top layer. If for whatever reason you need additional height in the cavities, it's easy to adjust in the included scad-file.
ALTERNATIVE: If you don't have access to a pause-at-z printer, then you could slice the bottom of the model off, print the body and bottom separately, and then glue together the entire object.
QUALITY: Make sure to slice the pin with no additional shells, as the links of the molecule are less than 1.6mm (4 nozzle-diameters) wide, and would wind up not being filled by the slicer.
The included scad-file is customizable based on the slicer's layer height, the diameter of the magnets, and how much horizontal space is placed around each magnet. It additionally echoes out the height at which the print should be paused. However, since Customizer does not yet support the import() command, I have just exported three of the most likely settings people would want to use if they happen to have 5mm Buckyballs on hand:
Params: 0.27mm layer-height, 5mm magnet-diameter, 0.17mm magnet-gap
Echoes: "Pause at 5.81mm"
Params: 0.2mm layer-height, 5mm magnet-diameter, 0.17mm magnet-gap
Echoes: "Pause at 5.6mm"
Params: 0.15mm layer-height, 5mm magnet-diameter, 0.17mm magnet-gap
Echoes: "Pause at 5.45mm"