While I am dredging my hard drive, here is a system-x project I built for my young nephew, a few years back. It is a spaceship he christened "The Lightning Bolt", and is the ship featured in the
Space Patrol HQ illustration I made during the "corona confinement" [ shudder ]. I am listing it here because it is a bit too big to be considered a ship or vehicle ( although
it is a spaceship ), and is closer to a building / fortress diorama.
The ship was designed in a 3D program, first, to figure out the structure, as well as which pieces to buy ( plates, in particular ). Obviously, steck was out of the question.
Though, to be honest, I believe steck
could be used to create futuristic bases, with conventional walls ( instead of stone masonry, imagine gribbled wall-sections, with pipes and panel lines ). In fact a mix of steck and system-x might work, for that use case ( think: underground, futuristic fortress, as opposed to a ship ). Anyhow...
The Lightning Bolt comes in two configuration: four-decker ( aka. "Phase 2" ), which was never built, and 3-decker ( aka. Phase 2B ). Note: Phase 1 was the original: a 3-decker version with some structural issues ( misaligned decks ), which
was built.
4-decker version:
3-decker version: