Simil-hatch between two polilines made by perpendiculars

I am trying to writing a small lisp to do following thing between two polylines:

It must:

select first polyline

divide it in n parts -> get computed points.

From each point, draw a segments perpendicular to the first polyline that stops at the second polyline.

Every two segments, break the drawn segment in two parts and delete one part.

I don't know how to start writing my lisp

Thank you a lot.

I FOUND this autolisp but it doesn't work in AUTOCAD 2014:

(defun C:PLWEB ()
 (command "_.undo" "_begin")
 (setq
   poly1 (car (entsel "\nSelect first Polyline: "))
   poly2 (car (entsel "\nSelect second Polyline: "))
   segs (getint "\nDivide first Polyline into how many segments? ")
   seglen ; length of segment along 1st Pline
     (/
       (vlax-curve-getDistAtParam
         poly1
         (vlax-curve-getEndParam poly1)
       ); end getDist
       segs
     ); end getDist and length1
   inc 0
   osm (getvar 'osmode)
 ); end setq
 (setvar 'osmode 0)
 (repeat (1+ segs)
   (command
     "_.line"
     (vlax-curve-getPointAtDist
       poly1
       (* seglen inc); position along 1st Pline
     ); end getPoint
     "per"
     (vlax-curve-getClosestPointTo
       poly2
       (getvar 'lastpoint)
     ); end getClosest
     "" ; end line
   ); end command
   (setq inc (1+ inc))
 ); end repeat
 (setvar 'osmode osm)
 (command "_.undo" "_end")
); end defun

This is the error:

Specify first point:
Specify next point or [undo]: per to
No Endpoint found for specified point.
Point or option keyword required.
; error: Function cancelled
Specify next point or [undo]:

Hope it helps. Thank you again