In a unique research cooperation between Stratasys, Education, R&D departments and MIT's Self-Assembly Lab, a new process is being developed, known as 4D Printing. The 4D printing concept, which allows materials to "self-assemble  " into 3D structures, was initially proposed by Massachusetts Institute of Technology faculty member Skylar Tibbits. Tibbits and his team combined a strand   of plastic with a layer made out of "smart" material that could self-assemble in water. They advanced this concept by creating materials that can change into several different complicated shapes, though this kind of material remains the bottleneck of 4D technology. To many people that are just starting to get used to the idea of 3D printers, the name 4D is causing confusion because they cannot understand where this fourth "dimension" coming from. 4D technology shares many of the same principles of 3D printing and is essentially still about creating a new, 3D structure out of certain component; however, Tibbits states the fourth dimension at work here comes from concept of the fourth dimension of time. The difference between these 3D and 4D creations is that these new forms have the ability to transform and adapt over time. 4D printing works through self-assembly -- a system where "disordered elements form an "ordered" structure via an interaction. With these 4D printed materials, these disordered materials are strands or sheets of specially designed materials. Environmental changes then stimulate  a response from them so that they form a preprogrammed shape. The idea of having adaptable technology that only relies on energy and non-human interactions raises some interesting questions about where 4D printing can be used and the practical applications in dangerous environments. This could mean improved infrastructures in extreme conditions, leading to a reduced need for workers to put themselves at risk, but the potential goes even further than that. The technology promises exciting new possibilities for a variety of applications. A solar panel or similar product could be produced in a flat shape onto which functional devices can be easily installed. It could then be changed to a compact shape for packing and shipping. After arriving at its destination, the product could be stimulated to form a different shape that serves its function. Also it could be used to build furniture, bikes, cars and even buildings. As with many of the ideas being put forward, it is easy to go a step too far into the extreme, but this just shows the potential of 4D in comparison to 3D. The next stage for the research is to move from printing single strands to sheets and eventually whole structures. And water need not be the process ' s only energy source. The major problem concerning the development of 4D printing lies in   _  .
producing essential 4D printers creating proper smart materials providing a suitable environment promoting practical applications