FIG. 4 is a cross-sectional side view of system 36 in which devices 10A and 10B are supported by a foldable support structure such as cover 38. Cover 38 of FIG. 4 has hinge structures 40 that help hold cover 38 in a desired bent shape (e.g., to support device 10B at an non-zero angle with respect to device 10A, so that device 10A can serve as a touch sensitive virtual keyboard while device 10B serves as a display for presenting a document or other content to a user, etc.). Hinge structures 40 may be formed from interlocking rotatable structures (e.g., a clutch barrel assembly), may include bendable metal or plastic structures (e.g., bendable strip-shaped members that retain their shape when forced into a particular bent or flat position by a user), or other hinge mechanisms. Hinge structures 40 allow a user to place devices 10A and 10B in a planar configuration (e.g., lying flat on a table so that devices 10A and 10B and their respective displays lie in a common plane) or in a bent configuration of the type shown in FIG. 4 in which the surface normal of the display of device 10A is oriented at a non-zero angle with respect to the surface normal of the display of device 10B and which devices 10A and 10B do not lie in a common plane). Attachment structures 42 (e.g., straps, magnets, adhesive, screws or other fasteners, clamps, etc.) may be used in removably attaching devices 10A and 10B to cover 38.