What is claimed is the ornamental design for a book bag, as shown and described.
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
FIG. 1 is a front view showing the book bag of Applicant's invention.
FIG. 2 is a left side elevation of the book bag of Applicant's invention.
FIG. 3 is a back view of the book bag of Applicant's invention.
FIG. 4 is a right side view of the book bag of Applicant's invention.
FIG. 5 is a top view of the book bag of Applicant's invention; and,
FIG. 6 is a bottom view of the book bag of Applicant's invention.