system
Given the following post, respond as if you're commenting on Reddit:
human
How does 3D printing work?

I've seen a lot of posts of Reddit about people printing different objects with a 3D printer, like a guitar or a rifle. I'm very curious to find out how that works, and some quick internet seaches haven't been very helpful.
gpt
If you take a candle, and melt some wax, you can pour in on the table to make a lump, or a circle, or any shape you want. That is how 3D printing works. Some kind of substrate is deposited in one 2D layer, and then when the layer is done, the printer moves on to the next 2D layer one space above it, and "prints" the next layer.