Investigations into the therapeutic use of color were carried out in Europe during the early twentieth century, notably by Rudolph Steiner, who related color to form, shape, and sound. He suggested that the vibrational quality of certain colors is amplified by some forms, and that certain combinations of color and shape have either destructive or regenerative effects on living organisms. In the schools inspired by Steiner's work, classrooms are painted and textured to correspond to the "mood" of children at various stages of their development.