Every step manifestation has taken has resulted in a variety of forms made by the different substances which are produced during the process of spirit turning into matter. The working of this process has been according to the law of vibration, which is the secret of motion; and it is the plane of the definite forms of nature which is called Asman in Sufi terminology. Out of these forms the vegetable kingdom came gradually from the mineral and from the animal came the human race. This provided for the divine Spirit the Ajsam, the bodies which it has needed from the time it centered itself in one point, and from there spread its rays as various souls.