This diagram shows a pair of axes. The X axis is labelled I and has points minus 3, minus 1, 1 and 3 marked on the axis. The Y axis is labelled Q and likewise has points minus 3, minus 1, 1 and 3 marked on the axis.
There are 16 dots positioned between the axes in a square formation, four rows of four. There is a dot at the intersection of each of the points marked on the axes. Thus the dots are spaced at regular intervals, the same distance apart.