10 WIDTH19
20 FORX=3TO15STEP6:GOSUB40:NEXTX
30 GOTO30
40 SX=1:SY=1:PX=X:PY=Y
50 LOCATEPX,PY:PRINT"*":PX=PX+SX:PY=PY+SY
70 IFPX=XANDPY=YTHENRETURN
80 IFPY=18ORPY=0THENSY=SY*-1
90 IFPX=18ORPX=0THENSX=SX*-1
100 GOTO50