Yet repetition alone is not sufficient for the purpose. In order to engrave a certain figure upon a stone, a line drawn with pencil is not sufficient; one has to carve it. And so in order to make a real impression of an idea, deeply engraved on the subconscious mind, an engraving is necessary. That is done by the repetition of a word suggestive of a certain idea. No repetition is wasted; for every repetition not only completes it, but deepens it, making thereby a clear impression upon the subconscious mind.