10	!
	!	YING-YANG PROGRAM
	!
12	!
	!	KEYED IN BY TIMOTHY SHANE MCCOY
	!	AT CENTRAL STATE UNIVERSITY
	!	ON PDP 11/45
	!	VERSION RSTS/E  V06C
	!
15	Q = 1
16	OPEN "KB:" AS FILE 1
20	DEF FNC(X) = SQR(1-X*X)
30	DEF FNS(X) = -SIN(PI*X)/PI
40	W = 30
50	L = 5/8*W
60	FOR X = -1 TO 1 STEP 2/L
70	FOR Y = -1.2 TO 1.2 STEP 2/W
100	IF Y > -FNC(X)
	THEN 200
120	GOTO 1000
200	IF Y > FNS(X)
	THEN 300
210	IF ABS(X+.5-Q/2) > Q
	THEN 280
220	IF ABS(Y+.5-Q/2) > Q
	THEN 280
260	GOTO 1000
280	REM
290	GOTO 1020
300	IF Y > FNC(X)
	THEN 400
310	IF ABS(X-.5+Q/2) > Q
	THEN 380
320	IF ABS(Y-.5+Q/2) > Q
	THEN 380
360	GOTO 1020
380	REM
390	GOTO 1000
400	GOTO 1020
1000	PRINT #1,"X";
1010	GOTO 1030
1020	PRINT #1," ";
1030	NEXT Y
1040	PRINT #1
1050	NEXT X
32000	END