It's strongly believed that cas is a "character assembler".  The input
describes character shapes, and the output is data for GRAPHICS-2.


CAS INPUT SYNTAX
================

: means record following string as a label.

x means following moves are invisible.

v means following moves are visible.

r means end, output label=x-b+number.

All other commands are character pairs denoting y,x coordinates in a
12x14 character raster.  Draw a line to that coordinate.  Vertical
coordinates are a-l, and horizontal are a-m.  aa is upper left and mn
is lower right.  All characters end with a "x mn r" sequence to move
to the beginning of the next character.


CAS OUTPUT
==========

The output for each character is:

The label x:

18-bit octal words. Each word is three 6-bit incremental moves.

label=x-b+number.  Number is 01, six bits saying how many moves, and
10 zeroes.


EXAMPLE
=======

Input:

   :lbk
   x
   ai
   v
   af
   mf
   mj
   x
   mn
   r

This character is labelled "lbk" (left bracket).  Move invisibly to
"ai" near upper right.  Draw line left to "af".  Draw down to "mf".
Draw right to "mj".  Invisibly move to "mn" beoynd lower right.  End.

Output:

   x:
   0010101
   0010101
   0010160
   0567474
   0747262
   lbk=x-b+0236000

01 means move diagonally up and right one step; do this eight times.
60 means move up four steps.  56 means draw left three steps.  74
means draw down four steps.  72 means draw left four steps.  62 means
move left four steps.

0236000 means there are 15 moves, or 6-bit bytes.