The ornamental design for a storagebox, as shown and described.
FIG. 1 is a front elevation view of a storage box;
FIG. 2 is a rear elevation view thereof;
FIG. 3 is a left-side elevation view thereof;
FIG. 4 is a right-side elevation view thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is a bottom plan view thereof;
FIG. 7 is a perspective view thereof;
FIG. 8 is an open state view thereof; and,
FIG. 9 is a use state view thereof.
The broken lines in FIG. 7 illustrating wheels of the storage box represent the environment of the claimed design and form no part of the claimed design.
The broken lines in FIG. 8 illustrating interior features represent unclaimed portions of the storage box and form no part of the claimed design.
The broken lines in FIG. 9 illustrating additional storage boxes represent the environment of the claimed design and form no part of the claimed design.