5 REM ========
6 DIM A$(1)
10 GRAPHICS 8
20 X=10:Y=20
30 DX=5:DY=5
40 CLS
45 PRINT "PRESS Q TO EXIT"
50 X=X+DX
60 Y=Y+DY
70 COLOR 1
80 CIRCLE X,Y,5
90 PAUSE 2
95 A$=INKEY$
96 IF A$="Q" THEN GOTO 150
100 COLOR 0
110 CIRCLE X,Y,5
120 IF (X<10) OR (X>310) THEN DX=-DX
125 IF (Y<10) OR (Y>150) THEN DY=-DY
130 GOTO 50
150 GRAPHICS 0