JSP 檔
參考自: A.B. Kempe, How to Draw a Straight Line, a Lecture on Linkages, p. 29
R.C. Yates, Linkages, NCTM 18th Yearbook, p, 121.
參考資料: C.M. Hebbert, A Cardioidograph, Amer. Math. Monthly, Vol. 22 (1915), pp. 12-13.