Each product are so differently designed such that consumer get all functionality of product but not same design. If let say the design of handphone and computers remain same for 20 years there are no advancement for the items. What create new designs, where are the inspirations from, a lot of time new item designs depends on the electronic parts, to make sure the parts function at most consumer desires, for example you introduced telephoto lens to handphone,what makes the telephoto lens function the best when you ask the electronic components manufacturer then it is the best design.
Extra designs include introducing extraordinary designs or designs which look too abstract to accept, and let some users use in a survey conducted. Next adjust the designs and only leave the ones which users feel great with it.