isection to diffuser

[JONTHEPOPE]

My code need's alot of love please insert below

this code is kind of what i want but as rec top

duct after with promt for size . not isec as is . please debug

code to look like pic please

  
(defun diff ()
(setq p1 (getpoint "\n Enter the starting point of diffuser: ")
     l (getdist "\n Enter the length of diffuser: ")
     w  (getdist "\n Enter the width of duct: ")
     t1 (getdist "\n Enter thickness of duct: ")
     t2 (getdist "\n Enter length of duct: ")
     p2 (list (+ (car p1) w) (cadr p1))
     p3 (list (car p2) (+ (cadr p2) t1))
     p4 (list (-(car p3) (/(-w t2) 2)) (cadr p3))
     p5 (list (car p4) (+ (cadr p4) (-1 (* 2 t1))))
     p6 (list (car p3) (cadr p5))
     p7 (list (car p6) (+ (cadr p6) t1))
     p8 (list (car p1) (+ (cadr p1) 1))
     p9 (list (car p8) (- (cadr p8 t1))
     p10 (list (- (car p5) t2) (cadr p5))
     p11 (list (- (car p4) t2) (cadr p4))
     p12 (list (car p1) (cadr p11))
)
(command "pline" p1 p2 p3 p4 p5 p6 p7 p8 p9 p10 p11 p12 "")
)  

bad.dwg