Tetrad Upholstery Alexia Loose Cover Sofa. The Alexia, in machine washable, yarn-dyed fabrics, comprises two sofas, a chair, and a footstool. Multi-channeled feather back cushions and scatters make Tetrad’s Alexia a classic upholstery range that will sit well in all environments. Available in a wide selection of washable and dry cleanable fabrics.