The mark consists of a front facing butterfly in the colors purple and yellow, with the butterfly shown at the left of the word "MI" which is centered above the word "TESORO", with both words appearing in a stylized form with only the letters "M" and "T" capitalized. The letter "M" is filled in with yellow, red, and green left diagonal stripes, and the letter "I" is filled in with red, green, and blue horizontal waves. The letter "T" is filled in with the color blue and has sporadically placed purple colored polka dots outlined in the color pink. The letter "E" is filled in with purple, yellow and pink colored horizontal waves. The letter "S" is filled in with yellow, red, and green colored left diagonal stripes. The first letter "O" in the trademark is filled in with the color blue and has sporadically placed purple polka dots outlined in the color pink. The letter "R" is filled in with purple and red colored plaid, and the last letter "O" in the trademark is filled in with the color teal with sporadically placed black square outlines framed by a white border on only the left side and top of the squares. There is a side profile butterfly in the colors purple, yellow, and blue centered under the adjacent letters "S O". All wording and design elements in the trademark are outlined in the color black.