(defun pl_pt(ss pt / ne e n)
(setq en (nentselp ss) e (car en))
(setq e (car en))
(setq n (fix (vlax-curve-getparamatpoint e (vlax-curve-getclosestpointto e (cadr en)))))
(nth (- pt 1) (list (vlax-curve-getpointatparam e n) (vlax-curve-getpointatparam e (1+ n))) )
)