A violin is not a piano. Composers wishing to gain familiarity with the arrangement of pitches on the violin fingerboard could use a set of keyboards arranged like this:
Description
To make this setup more violin-like, the following limitations could be imposed:
Scales on this keyboard are similar to scales on a violin fingerboard: the four fingers per string corresponds to four fingers per section (and the thumb can be used to play the "open" string if necessary).
Where this keyboard would be especially useful is in gaining familiarity with possible double/triple/quadruple stops. Improvision on this keyboard would give a composer the kind of intuitive familiarity with "what lies under the fingers" that would otherwise only come from learning to play the violin.
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