#define RED_BUILTIN 13
#define GREEN_BUILTIN 12
void setup()
{
pinMode( RED_BUILTIN, OUTPUT );
pinMode( GREEN_BUILTIN, OUTPUT );
}
void loop()
{
digitalWrite( RED_BUILTIN, HIGH );
digitalWrite( GREEN_BUILTIN, LOW );
delay(2000); // wait for 2 secs
digitalWrite( RED_BUILTIN, LOW );
digitalWrite( GREEN_BUILTIN, HIGH );
delay(1000); // wait for 1 sec
}