10 @ARUN:'*RAILROAD CLOSSING
20 L=1:OUT 0
30 PWM 2,140
40 WAIT 30
50 IF !BTN() CONT
60 @CLOSE
70 PWM 2,60
80 OUT L,0
90 L=6-L
100 OUT L,1
110 BEEP
120 WAIT 20
130 IF !BTN() GOTO @CLOSE
140 RUN