The mark consists of a square-shaped image having open edges along each of four (4) sides with a pair of arrowed linear segments each formed having a right angle internally formed in the upper left and lower right corners of the image. In the lower left corner of the image, a capital letter "M" stands upright on the bottom edge of the image with its leading leg positioned to align with and frame in part the left edge of the image beneath the arrowed linear segment in the upper left corner. In the upper right corner of the image, number "21" in stylized form is positioned above and to the right of the trailing leg of the "M" with the "1" being aligned with and framing in part the right edge of the image above the arrowed linear segment in the lower right corner.