10 LET C=-.8
 20 LET D=.156
 30 FOR V=43 TO 0 STEP -1
 40 FOR H=0 TO 63
 50 LET X=(H-32)/21
 60 LET Y=(V-22)/21
 70 FOR A=1 TO 50
 80 LET R=X*X-Y*Y+C
 90 LET I=2*X*Y+D
100 IF R*R>1000 THEN GOTO 150
110 LET X=R
120 LET Y=I
130 NEXT A
140 PLOT H,V
150 NEXT H
160 NEXT V