Taste the incomplete rainbow...

While in the middle of my biology paper my mind wanders. For an unknown reason my ADD brings me the topic of skittles. In thinking about skittles and how you are suppose to taste the rainbow I realize there is no blue skittle. Why isn't there a blue skittle??? The rainbow is not complete!!! Blue is my favorite color. I just don't understand. First of all artificial blueberry flavoring is delicious! Second of all kids love turning their mouth colors and the color that turns your mouth the most is blue! I want answers....Back to Biology...