4D printing is here. What is 4D printing you ask? 4D printing produces a 3 dimensional object with a time component. Once produced, objects change over time with the application of water, heat or light.
Lest it sound impractical or even fictive, consider this quote from a great Discovery.com article by Evan Ackerman entitled: “4D Printer Makes Shape Shifting Wood:” “Such “programmable materials” may one day mean that you can buy flat-pack furniture at IKEA, take it home, spray it with a garden hose and then watch it assemble itself. We don’t even have to speculate: MIT is working on this exact thing.”
Programmable Wood by Skylar Tibbits
Self-Assembly Lab - MIT
The authors explain that that wood naturally warps with the addition of water. So, “with a comprehensive understanding of how the material behaves, along with computer models, you can 3-D print a piece of artificial wood that’s been “pre-programmed” -- using carefully constructed layers of various thicknesses and grain directions -- to warp itself from flat into exactly the shape you want. Just add water.”