The secret is that making Art, creating things, is a transformative process. The act of creation takes certain elements of our psyche, energy, if you will, and morphs it out of our heads and into the real world. Matter can neither be created nor destroyed, but it can be alchemized. The reason why Art works so well in therapy is that it allows for negative energy and/or trauma to be cleared out of our heads, and turned into something productive, without having to speak about things literally. Pictures can communicate energy without words, and in so doing, can tell stories that would be otherwise stuck in the murky world of the subconscious. The act of creation is akin to shining light on our shadows, (Jung again) and it enables the creator the opportunity to move on. Catharsis.