There really is no boundary. The goal is to stimulate creativity. If the plastic plant roof has meaning and purpose beyond just looking unique then then i would want to hear about it. I think that what ever we do that is creative must be a mix of art with purpose. A lot of people end up posting cool pictures on Land8, but without explanation they just look like art. If they also included what those pictures mean then i would really be able to learn something. Here in “out of the box” I want to see and hear about all of the unique things people are doing so I can learn and be inspired by them. When people post what appears to just be art, I am impressed with their rendering abilities but that is all that I get out of it. Show and tell me what your doing, but then tell me why you did it and what you learned in the process that makes the site or project better. I don’t know if I have really answered your question or not. I think that anything goes in “out of the box” just be prepared to answer questions that teach us something about your project or you.