The ornamental design for a twin double bunkbed, as shown and described.
FIG. 1 is a front perspective view of the design showing the front, top and
left hand end of the design. The right hand end of the design is, in
peripheral outline, a mirror image of the left hand end of the design and
its surface is flat and unornamented; and,
FIG. 2 is a front view of the design.
The portion of the article below the slatted mattress support is not part
of the claimed design. The portion of the slats and the slat support at
the front of the article which is not seen in FIG. 1 is a mirror image of
the like portion of the slats and the slat support at the rear of the
article. The rear of the article is not part of the claimed design. The
inside of the footboard not shown is the same as the inside of the
headboard shown in FIG. 1.