Going green is the cool thing to do nowadays. And if you can’t entirely go green, well you start making compromises. DVD, Blu-Ray, and all other sorts of cases have been doing this recently. And while the DS, to my knowledge, dodged the bullet, the 3DS will be right out the gate with eco-friendly cases.
After the jump you can see that the case is filled with holes to save plastic. Twelve on the left and eight on the right, making for twenty holes in your case.
Right now it is unclear if these are the only cases that will be available. These eco-friendly cases seem to be case by case scenarios on some platforms, usually depending on the publisher. Either way, be careful not to bump your case on sharp objects!