10 GR
15 COLOR=5
20 Y = 0
30 X = 0
40 IF (20-X)*(20-X) + (20-Y)*(20-Y) < 100 THEN PLOT X, Y
50 X = X + 1
60 IF X < 40 GOTO 40
70 Y = Y + 1
80 IF Y < 40 GOTO 30