Composite Semaphore Flags are based upon the two hand signal semaphore flag positions that convey alphabetical information. Like Maritime Flags, each flag symbolizes a letter. The central dots represent the human head of the person who would normally be holding two flags, usually the Oscar Flag.
The background colours of the letters are based upon the ones digit value as coded to the visible spectrum: with red being 1, orange being 2, yellow being 3, green being 4, blue being 5, indigo being 6, and violet being 7; and the colour black is coded to eight, pink is coded to nine, and white is coded to zero.
But note, the background colours for Composite Semaphore Number Flags are reversed with the associated contrast indicator, such that the central human figure retains the ones digit value colour.
Additional Composite Semaphore Flags also code for attention, negation, numbers, and space; but these flags do not follow the colour coded to ones digit value.
Also note that the stars indicate the right arm, which reflects the starboard-right side of the communicator. The port side, left arm, is blank.