By the threefold changes in the mind-stuff as to form, time and state are explained the corresponding changes in gross and subtle matter and in the organs. Suppose there is a lump of gold. It is transformed into a bracelet and again into an earring. These are changes as to form. The same phenomena looked at from the standpoint of time give us change as to time. Again, the bracelet or the earring may be bright or dull, thick or thin, and so on. This is change as to state. Now referring to the aphorisms 9, 11 and 12, the mind-stuff is changing into Vrittis — this is change as to form. That it passes through past, present and future moments of time is change as to time. That the impressions vary as to intensity within one particular period, say, present, is change as to state. The concentrations taught in the preceding aphorisms were to give the Yogi a voluntary control over the transformations of his mind-stuff, which alone will enable him to make the Samyama named in III.4.