Yeah, a hinge.
No but for real, you can only do that with either a hinge or a rotator.

Bummer, thanks. Hopefully this very simply addition makes it in eventually. Really puts a halt to my idea of a sphere hull with windows. :/ Hinges/rotators simply don't do it justice.

Hate to break it to you but the game operates on a cubic voxel-like grid and the only way to break it and make things at an angle, are mechanisms like these two.

Although, I highly encourage you to visit the official Discord server if you're looking for guidance.
Also, the game's Workshop page features builds which can inspire you to build what you want.

And when it comes to spheres made of glass, you can do that on a single grid with no mechanisms, though we're still waiting for one glass piece that will make it look slightly better and less obtrusive.

Ah, I see. Well, here's to new glass pieces then - I think I know the missing piece in question (glass hepta). I just hate how they interact with each right now, with the visible adjoining lines and all.