First, hello. Thanks for your very well documented return on my idea. The idea of the project is not to find an alternative to the cardboard. It is to solve the present and worldwide issue of the recycling of the cups. Like i wrote down on my page : the cardboard is plastified with PE (polyetylene). This makes weither the plastic or the cardboard almost impossible to recycle because very difficult to separate from each other in the end. To response to this issue, I propose a project of research and developing around the recycling of the cups. I think, at the moment, there is no magic alternative to cardboard. But what we can already do, is to recycle this carboard, not just throw away and let decompose because it would increase to much the entropy of materials. The production of carboard requieres ressources and energy. So it is not in the best ecological and economical interest to throw the cardboard away after a single use (like it happens with fiber cups nowadays). Second, sure I could develop the design of the fiber cup to be more stable and avoid at best the issue of overturning of the cup. Also, the idea is not to eliminate the plastic liner, but just to turn it into a plastic layer you can remove by pulling on it at the end of the use. So, the new plastic layer would still ensure the sealing of the cup and avoid the leaks... I hope I made myself clear.