In a nutshell: If you can dream it, you can build it. That isn't the slogan for Lego, but perhaps it should be after seeing what one Reddit user managed to piece together using the popular construction bricks.
Modern 3D printers come in all shapes, sizes, and price points, but I bet you haven't seen one quite like this before. Reddit user Zealousideal-Army333 recently showcased a fully functional 3D printer crafted almost entirely out of Lego. According to the builder, it utilizes large motors for the X, Y, and Z axis as well as a smaller one for pressing the button on the 3D pen.
The creation is coded using Python on ev3dev, we're told. It's a gen two model, and it took "forever" to build, the creator added.
LEGO 3D printer!
byu/Zealousideal-Army333 inlego
As of writing, Zealousideal-Army333 hasn't yet published a step-by-step build guide for the printer (and he probably won't considering he said he barely remembers how he built it). And even if you could replicate the build without too much trouble, you're likely better off just buying an off-the-shelf printer. A commercial unit would require no (or very little) assembly), would be far easier to use / program, and could certainly turn out higher quality prints. It'll probably cost far less in the long run as well, have a warranty, and be far more durable.
Zealousideal-Army333 shared a print created using the Lego printer – a 3DBenchy, which is a common 3D model design meant to test the accuracy and capability of your printer. The Lego-made 3DBenchy is rather rough around the edges compared to what you'd get from a commercial printer. Still, the fact that it works at all is impressive and many – myself included – would love to see the 3D printer spit out its own version of Lego bricks.
Who knows, maybe the folks at Lego will see this and get inspired to make their own branded 3D printer.