Scatter plots for the number of probes matching a reference sequence. Scatter plot of the total number of probes matching a reference sequence against the number of probes remaining after removing the probes matching several reference sequences. Colored areas are displayed to indicate the z-axis, the number of probes occupying each spot in the graph. A grid-like pattern can be observed in the lower-left corner of the plot. The size of the cells is 11 probes, which is the number of probes contained in most of the probe sets in the official mapping.