Imagine printing objects that are programmed to change with time. http://now.howstuffworks.com/2016/02/19/4d-printing-shape-changing-object
Here’s a direct link to video. https://www.ted.com/talks/skylar_tibbits_the_emergence_of_4d_printing?language=en#
Calling it now. Glowforge 2: The 4D Laser Printer
Prints in reverse time?
Prints spare time, for when you run out.
Oh, sign me up for one of those!