“Sai” product is an example of accessories (side products) in Mana Gheshlaghs category. The formation process of this product was defined and designed in order to organize the negative spaces. The main idea is the emergence of space envelopes and light roofs for combination and flexibility in the formation of Mana Gheshlagh products, which in the end result, is compatible with mana products and in function meets the diverse needs of users.