
These are mapping files for the qwertymidi utility.  In addition to being a
quick way to play melodies when you don't have a real synthesizer keyboard
handy, they're a fun way to explore esoteric, historical, expensive, or even
hypothetical instruments that you don't have access to in the real world.
I try to collect any which catch my eye and which fit, more or less, within the
confines of a qwerty keyboard.

I've long been fascinated by the notion of isomorphic instruments, ones whose
keyboard, button board, or fretboard layouts use the same finger motions to
produce the same relative intervals regardless of the starting note.  In
theory, this makes it easy to play in any key just by shifting your hand to a
different starting position.

In the mapping files for isomorphic layouts, I use a notation based on compass
directions to describe the primary and secondary axes of intervals as
conventionally visualized by the musician.  For instance, a violin has its
primary axis running up each string, along which the intervals are half steps.
On a qwerty keyboard, it's natural to represent this as moving along a row of
keys to the right or "east".  The violin's secondary axis corresponds to
jumping from a lower string to the next higher one, along which the interval
is a fifth or seven half steps.  Since the qwerty keyboard has staggered rows
of keys, we can't represent the secondary axis by moving straight upward, so we
need to pick a diagonal direction; for argument's sake let's pick up and to the
left or "northwest".  Putting it together, that makes the mapping for violin a
"1E/7NW" isomorphic layout.

