In Alejandro Jodorowsky's concept for a Dune film from the early 1970s, each house has their costumes and architecture designed by a contemporary artist. Giger was the designer for the Harkonnen, and several of his ideas persisted beyond the failed film.
The Harkonnen Castle
A Harkonnen chair
I assumed Villeneuve was calling back to those designs.
Cool, never seen these before. The designs were nice, the only thing I didn't get was that Harkonnens are now stark white bald people. Their ships were menacing, which is cool. But I think the original intention was that they were also human, not so different from the Atreides. Which I liked.