$ 'main'               /---o#
 \-0(!x!)--i-{i}--e{~}<
     @---/             \
       \-----------------@

$ 'i'
 \                           /-(!q!)(b)a#
  \--1(!b!)0(!c!)-{d}(c)q{~}<
                /            \
@--m(!b!)------/              \
  \--[0001]----(b)(!c!)a1(c)----@
   
  
$ 'd' (dup)
 \-(!d!)(d)(d)#

$ '~'
\
|   /-t-\ #
|  /     \|
\-<       |
   \     /|
    \-f-/ @