Could you refer to the following codes?
ACLS
FOR I=0 TO 15:SPSET I,340:SPHOME I,8,8:SPOFS I,1024,1024:NEXT I
X=200:Y=120:C=0
WHILE TRUE
VSYNC 1:STICK OUT SX,SY:SPOFS 0,X,Y,0
IF C==0 THEN
FOR I=1 TO 15
IF(SPCHK(I)AND #CHKC)==0 THEN SPCOLOR I,&HFFFFFFFF:SPOFS I,X,Y,1:SPANIM I,"C",-30,0,1:BREAK
NEXT I
ENDIF
X=X+5*SX:Y=Y-5*SY:C=(C+1)MOD 3
WEND