The Braille flag for the letter Z is orange and blue. The colours represent the number 25. However Z is the 26th letter in the alphabet. This is because the letter W was shifted to position 40, consequently Z gets a one spot upgrade to position 25 instead of its natural position of 26.
The Braille Letter X flag uses the colours orange and yellow. Together these colours represent the number 23, but X is the 24th letter of the alphabet. But this is how the Braille alphabet flows since W was shifted to position 40.
The Braille flag for W is a little different. The colours code for position 40, since green in 4 and white is 0. Normally W is the 23rd letter in the alphabet, but since Braille was created by the French, Mr. Braille, it was added later after it was widely adopted and spread the English speaking world. Another neat fact is that it is of the few brl symbols to resemble one of the famous Tetris pieces.
The Morse code for V has four elements, 3 dits and one dah. Likewise the Braille letter for V has for elements: three in a line and one by itself. Since V is the 22 second letter of the alphabet it gets two oranges that unite to make a whole orange flag. Remember 2 is coded to the colour orange since orange is dominantly recognized as the 2nd colour of the rainbow/spectrum. Ironically the Braille V erroneously spells out the letter L, and L is usually associated with the a loss or loser.
The Braille U flag is composed of an orange and red field. Orange is coded to 2 and red to 1. This makes the number 21, and U is the 21st letter in the alphabet. The brl dots are black because the assigned contrast indicator is black.
Tango is the one of the neat Braille letters that looks like a Tetris symbol. Here the flag for the Braille letter T has an orange and white field. Since orange is the second colour of the spectrum it is coded to 2 and white is coded to 0 as it represents all colours. Black is included because it is the assigned contrast minority indicator.