[[EPZ Thousand Plateaus - Gilles Deleuze Félix Guattari]] again in point Gilles Deleuze, Felix Guattari, A Thousand Plateaus, Capitalism and Schizophrenia, 42 > The two stages of cellular chemistry, therefore, differ in their function, products and nature. The first carves out chemical motifs; the second assembles them. The first forms compounds that exist only temporarily, for they are intermediaries on the path of biosynthesis; the second constructs stable products. The first operates by a series of different reactions; the second by repeating the same reaction." There is, moreover, a third level, upon which cellular chemistry itself depends. It is the genetic code, which is in turn inseparable from a double segmentarity or a double articulation, this time between two types of independent molecules: the sequence of protein units and the sequence of nucleic units, with binary relations between units of the same type and biunivocal relationships between units of different types. Thus there are always two articulations, two segmentarities, two kinds of multiplicity, each of which brings into play both forms and substances. But the distribution of these two articulations is not constant, even within the same stratum.