Found some funny upcycling method for bottles:
http://themetapicture.com/some-people-just-throw-plastic-bottles-away-others-make-this/
they making use of every specialist of a bottle, e.g. floating for boat; supporting for stool; shape for decorating; color for mosaic; etc.
I was inspired since usually we only see a few character from an item. This showing there are many possibilities from a very simple and common item.