Symbiosis, in biology indicates a type of coexistence between organisms of different species, animals or plants, called symbionts. In the case of Fossati's and Steiner's artistic practice, "symbiosis" happens with the natural materials (spores and mycelia) they made use of in the creation of the works. Materials that have risen to co-creators of the works themselves. Nature acts as a co-creator. In the natural environment they collect, they source, spores and mycelium. Of the collected matter they effect a transformation that they return to the environment, no longer only natural, in a form whose benefits cannot be immediately verified. The two artists dialogue from drawings of mushrooms made by Testori in 1987