//https://model-railroad-hobbyist.com/node/23026
//18/02/2025

#define numleds  16                                                      
byte ledpins [ ] =  { 0,3,4,5,6,7,8,9,10,11,12,13,A1,A2,A3,A4 } ;//0,3,4,5,6,8,9,10,11,12,13,A3,A2,A1,A0,A4,A5
void setup( )  {                   
    for ( int  i=1; i <= numleds;  i++ )  {      
    pinMode ( ledpins [ i ], OUTPUT) ;
    digitalWrite ( ledpins [ i ] , LOW) ;//HIGH
   }
}
void loop ( )  {   
                digitalWrite ( ledpins [ random ( 0, numleds+1 ) ], lightsw ( ) ) ;
                delay ( 5000 ) ;  //13000                 
}
boolean lightsw ( )  {
 if  ( random (0,100) > 50 ) return LOW ;//40
   else return HIGH ;
}