<turn left by 90 degrees
>turn right by 90 degrees
/turn left by 45 degrees
\turn right by 45 degrees
n%turn left by n degrees (n must be a non-negative integer)
(push state
)pop state
-lengthen bond
=increase bond type (single -> double -> triple)
'decrease bond type (single -> none)
|draw lone pair perpendicular to current direction
@draw a circle at the current position
.draw an invisible atom
,draw a "skeleton" atom