Some industrial companies, foundations and firms were always keen on setting their premises with representative artworks by renowned artists. They would also purchase, maybe not so often, artworks where an artist would showcase the vocation and character of the silent partner; this way, the procedures remind of the Renaissance patronage. In order to take up the accomplishment, it was necessary to find an artist capable of integrating his art to preexisting environment and forcing it beyond any restraint. Immediately, getting straight to the point, Castro suggested as a theme the word ATOCHEM and symbols used for the chemical nomenclature. Three murals by Castro, the polyptych in particular, show a surprising formal relation to the Spanish Apocalypses of the year one thousand.
The set of polyptich can be interpreted as a triple picture: material force of elements (horizontal diptych), a restraint to observe with regard to this force as well as an indispensable search of his mastery (large wheel): beneficial radiation that can be obtained by science from the transformation and recreation of matter (superposed coronas). Each of seven circular compositions forming the polyptich is distinct in its presence and dynamics. Their combined radiation can be also sensed in the reference to the infinitesimal space of atoms, the place where constellations unfold.
It is a diptych made in tribute to the chemical nomenclature: Abécédaire on the left, Chiffres on the right. The set measures 1m72 high by 4m90 wide. Castro chose to name it “Abécédaire” instead of “Alphabet” as an abécédaire is a textbook for learning to read. The word read has a double meaning: literary reading and visual one. The alphabet, on the other hand, is a list of all letters used for transcribing sounds of a language, arranged according to the established order.
Abécédaire is composed of two horizontal levels. On the upper level, there are five written vowels of the French alphabet; on the lower level, on a smaller scale, there are twenty one consonants. This disposition illustrates the relation between the consonants and vowels. The rhythm of forms and colours creates a flight of the consonants towards the vowels. The consonants corresponding to the vowels were placed beneath the latter. The artist states that he wanted to show in this artwork how “the vowels voice the consonants”. There are three pairs of colours in the composition: black and white, red and blue, yellow and green. Every colour is built underneath another, that is, twelve colours in total.
Chiffres are equally composed of two levels: on top there is a zero and four even numbers; at the bottom – five odd numbers; the scale of the numbers is indicated on both levels. This disposition illustrates the position of the zero – sifr in Arabic – giving origin to the word “chiffre”, a famous “invention” of Arabic numbers; as well as the privileged place of number 5, considered as an equivalent to the symbol of man. Four pairs of colours are featured in the composition: two blacks, two whites, two grays, and two blues. These eight colours are built below eight different ones, that is, sixteen colours in all.