special $raw_text$[lay=lay_value] point_list
Here $
can be any character and is used to delimit the start
and end of raw_text.  The command embeds raw_text in the
sketch output after performing substitutions as follows. 
     
#i where i is a positive integer is replaced by
the i'th point in point_list. 
#{i} is also replaced as above. 
#i-j where i and j are positive
integers is replaced by a string {angle} where
angle is the polar angle of a vector from the i'th point
in point_list to the j'th. 
#{i-j} is also replaced as above. 
## is replaced with #. 
The only useful option of special is lay. 
See Internal options.