5 SIGNAL = 0
10 CLS
15 FOR SIGNAL = 1 TO 5
20 FOR I = 400 TO 800 STEP 9 :SOUND I,1:NEXT:FOR I = 800 TO 400 STEP - 9:SOUND I,1:NEXT
25 NEXT
50 FOR I = 400 TO 200 STEP - 8:SOUND I,1:NEXT