0 REM    GRAPH
10 (null)1:(null)1:(null)1
20 (null):(null)1:(null)7,0
30 (null):POKE53280,0
40 :
50 DEF FNA(X)=COS(X)-COS(2*X)+COS(4*X)-COS(8*X)
60 MX=160:MY=100
70 (null)MY:(null)MX
80 FORI=0TOMYSTEP20:(null)MX,MY-I:(null)MX,MY+I:NEXT
90 FORI=0TOMXSTEP20:(null)MX-I,MY:(null)MX+I,MY:NEXT
100 PA=0:YA=MY-(20*FNA(-MX/20))
110 FORP=1TO319
120 X=(P-MX)/20:Y=FNA(X)
130 YY=MY-(Y*20)
140 IFYY<0ORYY>199THEN160
150 (null)PA,YA,P,YY
160 PA=P:YA=YY
170 NEXT
180 (null)0,190:PRINT""SPC(255)SPC(255)SPC(255)"   PLEASE PRESS 'SHIFT'!";
190 WAIT653,1:(null)