Composite Semaphore Flag for the Letter Y - Yankee
The Composite Semaphore Flag for Yankee has a blue background,
because Y is the 25th letter of the alphabet. Reason being, 5 is coded
to blue and the ones digit value of a letter sets the colour. As a
reminder blue is the fifth colour of the spectrum. Also the stars
represent the right-starboard arm of the Semaphore Signaler.