So simply take a photo of someone, preferably 3D.
Then have a 3D printed image of that photo, and there you have it.
The ability to unlock your phone using facial recognition.
Extrapolate a little, add a little imagination and we have a hologram version of that 3D print on one phone unlocking another.
Anyone who doubts that ID theft is the next big thing, may be in for a shock.
How far will the quest to be "secure" go?
Time will tell
https://techcrunch.com/2018/12/16/3d-printed-heads-unlock-cops-hackers/