Such studies serve to also highlight the complexity of base arrangements in a DNA sequence and the difficulties in finding any inherent pattern or signal sequences in such arrangements, especially in a character based representation of the hundreds and thousands of nucleotides comprising the sequences. However, a graphical representation can be expected to provide visual clues to any inherent pattern or regularity as distinct from a purely random distribution of the bases which could be expected to generate a corresponding random distribution in the representative plot. Indeed, a purine-pyrimidine sequence map proposed by Peng et al [7] provided a visual rendition of the growth of purine and pyrimidine numbers in a DNA sequence, which was interpreted by the authors as indicative of an inherent fractal nature in the purine-pyrimidine structure of the DNA sequences. The chaos generator representation of Jeffreys [8] with its double-scoop depletion pattern reflected largely the abundance, or sparseness, of various dinucleotides and higher combinations, and also showed characteristic variations for different classes of organisms.