Inline chromatic harp
An inline chromatic harp is a harp where the strings for all 12 chromatic notes of the octave are placed in one row (the same way strings are placed on a standard concert harp), as opposed to their being placed in two or three (parallel or crossing) courses.
Single course inline chromatic harps have been produced for at least the past 110 years: in 1902 Karel Weigel of Hanover (Germany) patented a model of inline chromatic harp. He built at least one 54 string (4 octaves and a fourth) model which is now housed in the Deutsches Museum (Munich).
A disadvantage of inline chromatic harps is that glissandi can only be performed chromatically.