Here's the theory. You print something, then as it's printing you pause the print at specific points and drop a buckyball magnet into the print. Then you continue the print and let the bucky ball get sealed off.
Here's how it works in real life. Not very well. First of all you have to fight the super strong magnets that would rather attach to each other than sit in an indentation. So you end up covering the already filled holes with your fingers to keep the balls in. But because you've manipulated the print when it resumes the new layers don't stick as well to the old one. Never mind the temperature control problem, the alignment is off.
I thought the Magnetic Minecraft Steve my thingiverse user UXO would be a perfect opportunity to try this process out. If it worked I could make my own and adapt it. But as you may have guessed it didn't. The model itself had a few problems, like the horizontally aligned holes for the shoulder sockets, but I fixed those and made the head blank, suitable for custom skinning. So the process should have worked. But it just didn't. Over and over again I tried and over and over again I failed. In the end this idea just had to be abandoned, which is a shame because I had some really cool ideas for it. Ah well.
I don't think the problems I had were particularly insurmountable. Just that I wasn't able to beat it before leaving on break. But maybe I will figure it out. Maybe PLA is the trick.