Mies van der Rohe's design principle of "less is more" and emphasis on functional amenities created a fine example of early functionalism architecture, a groundbreaking new vision in building design at the time. Mies used the revolutionary iron framework which enabled him to dispense with supporting walls and arrange the interior in order to achieve a feeling of space and light. One wall is a sliding sheet of plate glass that descends to the basement the way an automobile window does. Mies also designed all of the furniture (two types of armchair designed for the building, the Tugendhat chair and the Brno chair, are still in production).