 A general overview of these changes include the reduction of the seven basic figures—A, S, T, V, X, Y, Z—in the first version, to only four. Particularly remarkable is the disappearance of  Figure S,  an essential element in the first version, as well as that of figures V, X, Y and Z. In the case of V, its terms will be found in other sections of the text. The  Elemental Figure  and the  Demonstrative Figure,  incorporated in the Ars demostrandi, are removed as well. The name of the figures is changed. Instead of using letters, they are now designated First, Second, Third, and Fourth. In all of them, the terms shown in the first versions are substituted by letters, and the meanings of these letters, in each one of the figures, are found in an “alphabet”. In addition, only 9 out of the 16 terms contained in them remain, for the new base of the formulation of the Ars is a ternary model, and not a quaternary one.