This caution was overcome by the discovery of such techniques as frottage and decalcomania. He belonged to the surrealist school, and invented the technique known as "decalcomania". He also explored with the technique of decalcomania, which involves pressing paint between two surfaces. The decalcomania was applied over an already glazed surface and re-fired. Decalcomania, a technique used by artists such as Max Ernst, can produce fractal-like patterns. Within the decalcomania you'll see different objects, the beaker, the piano, the desk scraping sound. German artist Max Ernst also practised decalcomania, as did Hans Bellmer and Remedios Varo.