Figure 2: Codons were sorted according to the order, symmetry and complementarity of their bases (left). The corresponding order of amino acids reveals periodicity of the physicochemical properties (polarity, charge, and molecular structure) of the encoded amino acids (right). Note that the periodic tables distinguish four separate fields, each corresponding to the four bases at the central codon positions. The frames of amino acid residues are rooted to the codons (boxes). The names of amino acids are indicated by one and three letters [5].