There are more elegant chain mail alternatives on here but this is my own experiment with alternately interlocked donuts in a hexagonal structure. I've minimised the polygon count but it's still a very greedy beast when it's slicing time. I left my old Intel Atom processor based box slicing late evening and found the chain mail section completing on my printer in the morning. Slicing took about 7 hours, printing just an hour and a quarter. I printed at 0.4mm layer height with a 0.45mm nozzle and the extruder set to 193 degrees. I'm still refining techniques, I've noticed that bringing temperature down a lot helps when printing out into space and extra thin layers don't turn corners out in unsupported space as well as thicker layers do. If I print this varian again I'd go for 0.3mm layers and drop the temperature a couple of degrees lower. This first design worked, printed to completion but then I spent most of an hour carefully working the links free from each other. If your printer has a built in support system it would of course be much cleaner.