Puzzle 1 answer

void
setup()
{
  pinMode( 13, OUTPUT );
}

void
loop()
{
  digitalWrite( 13, HIGH );
  delay( 100 );
  digitalWrite( 13, LOW );
  delay( 100 );

  digitalWrite( 13, HIGH );
  delay( 100 );
  digitalWrite( 13, LOW );
  delay( 100 );

  digitalWrite( 13, HIGH );
  delay( 100 );
  digitalWrite( 13, LOW );
  delay( 1000 );
}