I started doing the companion cube from Portal, but fucked up and didn't think even about reaching the sky roof when i started building it, which of course i did and it ruined the whole project...
I even drew schematics irl to figure out how i should get started, and i forget the most basic thing to check, to see if it would fit in the area i was working in. Im that awesome.
Probably won't bother with it anymore, no point if it can't be finished. On to the next project.