Label the horizontal axis as the x-axis, and allow every unit along it to have a y value of zero as you would in a rectangular coordinate grid system. Let the y-axis be the line of units that hits the center of the axis at a 60-degree angle. This grid labeling system closely resembles that of a normal coordinate grid, except that the y-axis is tilted instead of being perpendicular. Every unit will have an x value that describes how far to the left or right it is, and a y value that tells how far it is along the tilted y-axis.
Label the horizontal axis as the x-axis, and give every unit along it a y value of zero. Locate the point along the x-axis that has a value of zero. Two lines of hexagons hit the x-axis at that point, at angles of 60 degrees and 120 degrees. Label those lines the y-axis and the z-axis. Every unit on the grid will have a three-coordinate value that tells its position relative to the x-, the y-and the z-axes, respectively.
Label the center of the hexagonal grid (0,0), and label the units adjacent to it (0,1), (0,2), (0,3), (0,4), (0,5) and (0,6). Begin immediately to the right and go counterclockwise around the hexagon, so that you have a symmetric seven-hexagon cluster with the origin at its center. Notice that the cluster is surrounded by six identical clusters. Label the center of the cluster that’s immediately to the right of the original cluster (1,0), and label its surrounding hexagons (1,1), (1,2), (1,3), (1,4), (1,5) and (1,6). Repeat the process, going counterclockwise around the cluster.