http://www.autodesk.com/

Founded by JohnWalker 
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CategoryCompany
(defun C:SLOT ( )
 
	(setvar "CMDECHO" 0)
	(setvar "BLIPMODE" 0)
	(setq oldsnap (getvar "OSMODE"))

	(setq diam (getdist "\nSlot Diameter : ")
		lngth (getdist "\nSlot Length : "))

	(while

		(setq pt1 (getpoint "\nInsertion point:"))
		(setvar "OSMODE" 0)
		(setq pt2 (polar pt1 0.0 (/ (- lngth diam) 2.0))
			pt3 (polar pt2 (/ pi 2.0) (/ diam 4.0))
			pt4 (polar pt3 pi (- lngth diam))
			pt5 (polar pt4 (* pi 1.5) (/ diam 2.0))
			pt6 (polar pt5 0.0 (- lngth diam)))

		(command "PLINE" pt3 "W" (/ diam 2.0) "" pt4
			"ARC" pt5 "LINE" pt6 "ARC" "CLOSE")
		(setvar "OSMODE" oldsnap)
	);while
	(princ)