The ornamental design for a posterbed, as shown and described.
FIG. 1 is a perspective view of a poster bed according to an embodiment of the invention.
FIG. 2 is an end view of a headboard of a poster bed according to an embodiment of the invention.
FIG. 3 is a side view of a poster bed according to an embodiment of the invention, the view from the opposite side being a mirror-image thereto.
FIG. 4 is an end view of a footboard of a poster bed according to an embodiment of the invention; and,
FIG. 5 is a top view of a poster bed according to an embodiment of the invention.
The dashed lines illustrating the bed frame and the middle portion of the upper rails are for illustrative purposes only and form no part of the claimed invention.
The headboard and footboard are shown separately for convenience of illustration.