The mark consists of a cube positioned at a 45 degree angle whose two side surfaces are unshaded and whose top surface is shaded; the left side surface displaying the letters "TBP"; the whole cube ensconced within a larger L-shape polygon whose side surfaces are all unshaded and whose top surface is shaded; ensconced, in turn, within a second, larger L-shape polygon whose side surfaces are all unshaded and whose top surface is shaded.