A sofa can be transformed into a mattress. Also the product is transformed into four modules like a seesaw or blocks, offering a variety of play experiences for children. It is 130 cm wide, 130 cm long and 34 cm high. Children can create a seesaw or a circular structure, using it as their own space. Also the small internal frame and circular block can be utilized as a one-person sofa or a seesaw. The PU cover is used as an exterior, posing no health hazard to children. It is a non-toxic material, totally free of formaldehyde.