C	H U N D E K U R V E
C
	DIMENSION HX(4),HY(4),HX1(4),HY1(4)
C	DATA HX,HY/0.,0.,15.,15.,0.,15.,15.,0./
	READ(1,1) XKANT
1	FORMAT('KANTENLAENGE ? ',F8.0)
	CALL PLOTS(0,0,0)
	IPEN = 3
	HX(1)=0.
	HX(2)=0.
	HX(3)=XKANT
	HX(4)=XKANT
	HY(1)=0.
	HY(2)=XKANT
	HY(3)=XKANT
	HY(4)=0.
	V1 = XKANT / 10.
50	DO 100 I = 1 , 4
		J = IREM(I/4)+1
		V = SQRT((HX(J)-HX(I))**2+(HY(J)-HY(I))**2)
		IF ( V - 1. ) 999,60,60
60		HX1(I)=(HX(J)-HX(I))*V1/V
		HY1(I)=(HY(J)-HY(I))*V1/V
100	CONTINUE
	V1 = V / 10.
	CALL PLOT(HX(1),HY(1),IPEN)
	IPEN = 2
	DO 80 J = 1 , 4
		I = 5 - J
		CALL PLOT(HX(I),HY(I),IPEN)
80	CONTINUE
	DO 200 I = 1 , 4
		HX(I) = HX(I)+HX1(I)
		HY(I) = HY(I)+HY1(I)
200	CONTINUE
	GOTO 50
999	CALL PLOT(0.,0.,999)
	END