By sheer coincidence I bought some items last week (computer equipment ...) that came in boxes containing those pre-shaped cardboard forms to hold everything into place.
For some reason I saw this as a good opportunity to make some additional science fiction buildings for the next installment of our Antares campaign.
I trimmed the rough edges a bit, and added two spires from an egg carton, as well as some polystyrene half-domes I still had lying around (and that once served as chaos vortices in my Warhammer 3rd edition games over 20 years ago). I think they look convincing so far :-)
Next I should add some details (raid the box full of plastic bits), then spray paint the things and add more painting details such as numbers, decals, some weathering ...
I tend not to spend too much time on such projects, since the likelihood is they will be used once or maybe twice, and then end up as giveaways at the next con for whatever player thinks he can use them for his own games.