Models of several early, and later discarded, space shuttle concepts.

(Source: mpdrolet)

The Harmon Kardon RABCO was one of the first (or maybe the first) commercially available linear tracking turntable. It was for its time a striking piece of industrial design and a lovely object in assembly, conception and quality of materials. It was beautiful, solidly built, and completely impractical to own. 

Speaking from a lot of hands-on experience, it was maddeningly tedious to calibrate and the linear tracking mechanism fell disastrously out of alignment at the most Infinitesimal disturbance. This was especially problematic since simply playing a record was one of the Infinitesimal disturbances that threw it out of whack.