Created by Anna Holmquist and Chandra Ahlsell, the design of Twelve is based around 12 monumental arches. The arches vary from tall to big, rounded to flat, narrow to wide. In the shadow of each arch one of the participating designers has been invited to exhibit their work. While the arches are classical in form, their construction is experimental. Each is made from blocks of Ytong aerated concrete, a lightweight material with a matte surface that disguises a highly porous inner structure.