  Democritus regards the properties of atoms in combination as sufficient to account for the multitude of differences among the objects in the world that appears to us.  Aristotle cites an analogy to the letters of the alphabet, which can produce a multitude of different words from a few elements in combinations; the differences all stem from the shape (schêma) of the letters, as A differs from N; by their arrangement (taxis), as AN differs from NA; and by their positional orientation (thesis), as N differs from Z (DK 67A6).  These terms are Aristotle's interpretation of Democritus' own terminology, which has a more dynamic sense (Mourelatos 2004). This passage omits differences of size, perhaps because it is focused on the analogy to letters of the alphabet: it is quite clear from other texts that Democritus thinks that atoms also differ in size.