Doesn't really fit on a portfolio, but I'm still proud of building it: a treehouse in the forest next to my parents' house. I built it together with a good friend of mine.

I learned a lot, as it was modeled in Google Sketchup and we had to order wood and other materials. It was a big project with limited resources, so naturally many things went wrong and we had to change our plans a lot. In the end we never fully finished it, and a few years later it broke down during a storm (the structural integrity was not great). We learned how to set realistic expectations and basic engineering principles, and although I would do it completely differently now, I believe it was a formative experience.