1 CLS:A=1:B=1:FORZ=1TO3:READX:Y=18:FORS=1TO36:LOCATEX,Y:PRINT"*":X=X+A:Y=Y-B
2 IFX<1ORX>17THENA=-A
3 IFY<1ORY>17THENB=-B
4 NEXT:NEXT:DATA3,9,15
