The joke, here, of which there are two, is that of course you can't print another cartridge. You'd spend 5kg of plastic to print a 4.9kg cartridge.
The second joke is that while you could conceivably print a cartridge housing, and fill it with counterfeit filament, it still wouldn't work. This because Cube uses the same business model as HP or Stratasys (I assume) where the printer's cheap, but the cartridges are expensive. Both HP and Stratasys use cartridges with chips in them that keep track of how much filament's been used, and it's probably too much to hope that Cube cartridges will be as easy to hack[1] as Stratasys cartridges. A $5 cryptocard chip more than pays for itself if it doubles your profit margin, and if the printer phones home, it'll be real hard to break the scheme.
