The mark consists of a stylized block letter "S".
Beginning at the top and going left to right, the 2nd and 15th smaller blocks are yellow, the 5th, 7th, 10th, and 12th smaller blocks are red; the 3rd and 14th smaller blocks are green; the 1st and 16th smaller blocks are blue; the 6th, 8th, 9th, and 11th smaller blocks are purple; and the 4th and 13th smaller blocks are left uncolored.
STEWART