"en":        "em":
    -----     ---------
   |     |   |         |
   |  -  |   |  -   -  |
   | | | |   | | | | | |
   | | | |   | | | | | |
===========================

Measurements:
en top == 
tall outer edges == 	14'
arch height		 ==		



Segments: (hardware perspective)

    77777     777777777
   6     4   3         0
   6  5  4   3  2   1  0
   6 5 5 4   3 2 2 1 1 0
   6 5 5 4   3 2 2 1 1 0
===========================


I need a more intuitive model/arrangement for the elements on the JS software end...
How about just X,Y,Z[0..2] ?
The Z coordinate indicates which parallel LED strip is being addressed: near [0] or far [1].

Possible data structure:
horiz[0..5]
vert[0..9]

Got it: Draw as if the horiz & vert's are a large contiguous image.

horiz[0..2] <-- Gaps won't be rendered
vert[0..9] <-- Pixels above the sides of the arches won't be rendered