Apologies in advance.
Why do we continue to eat even after we're full? Spoiler: the answer isn't "because it tastes good."
This is fascinating. The more you know!
Short answer: The accelerometer. Longer answer that actually tells you the meat: EngineerGuyVideo breaks down a smartphone and both shows you and explains why this is the case.
Magic.Just kidding...clever angles, well-positioned lights, and a lot of drunk/high people that didn't notice the imperfections.
If you've heard of 3D Printers but never seen one in action, this video will blow your mind. The possibilities are virtually endless.