The mark consists of a configuration of numbers 1 2 3 4 5 situated in a vertical orientation in relation to one another from the lower part to the upper part, with each number 1 2 3 4 vertically positioned in the center of two equally opposed first set of horizontal lines above and below each number, with the number 5 vertically positioned in the center and above one of the horizontal lines in this first set of horizontal lines, and with the first set of horizontal lines each having substantially the same thickness, each number 1 2 3 4 5 horizontally positioned in the center of two other equally opposed horizontal lines consisting of a second set of horizontal lines situated to the left of each individual number and a third set of horizontal lines situated to the right side of each individual number, and with the second set of horizontal lines and the third set of horizontal lines each having substantially the same thickness, and the first set of horizontal lines having a different thickness than the second and third set of horizontal lines, and the first set of horizontal lines, second set of horizontal lines, and third set of horizontal lines each having a different thickness that is smaller than the numbers 1 2 3 4 5.