Fifty years ago, future architects, car designers and airplane designers didn't have home computers, but they did have the Pyro Plastics company (history here) which manufactured three interesting building sets with the more intellectual child in mind than usually played with Kenner sets and Lincoln Logs. I remember seeing them in offbeat places like trading stamp redemption centers rather than, say, standard department stores.
I myself had this set. While fun, I never understood the claim one could build four thousand models. I think they were cheating it a bit, by at least 3,900. One did not glue these sets if one didn't want to, so one could endlessly construct and reconstruct. The pieces fit together easily and held reasonably well. Included was a paper slide rule I could never figure out, which probably partly explains why I didn't end up designing planes.
I also wanted Design-a-Car.
The box art for the basic Design-a-House set. I've never seen a master set. If there's someone out there who has one, I'd love to see some pictures. I used to play with a friend's set and always wanted one myself. That finally happened when ebay shook out the attics and basements all over the world. Though easy to assemble, it's probably as close as any mere toy got to looking like a genuine architectural model.
A quick example of what one can begin do with the set. There are a lot more pieces in the box. The panels, shown as stud walls, can be covered in various shades of colored paper (included) to make them opaque. Rooflines can designed to be sloped or flat. One can design one or two story houses, in mid-century modern, of course. There are kitchen cabinets, bathroom fixtures, even a tiny toilet, cast in popular turquoise.