Just when you think you’ve seen it all… [Fergal Coulter] over on the RepRap forums just came up with a method of 3D printing on inflatable structures — wait what? The process uses a custom 3D printer ...

If you’re used to thinking about 3D printing in Cartesian terms, prepare your brain for a bit of a twist with [Joshua Bird]’s 4-axis 3D printer that’s not quite like anything we’ve ever seen before.