The mark consists of letters M, C, L and C and a plurality of horizontal lines arranged as follows: an uppercase letter "M" is left-most, and an upper case letter "C" is partially superimposed over the rightmost descender of the letter "M". That pportion of the letter "C" so superimposed is of contrasting color to the color of the descender of the letter "M" but no specific color is claimed. To the right of the letter "C" are the uppercase letters L, L and C vertically arrayed. Above the foot of each of the letters L, L and C are two horizontal lines parallel to the feet of said letters L, L and C.