FIG. 1 is a front perspective view of a first embodiment of the firebox.
FIG. 2 is a back perspective view of FIG. 1.
FIG. 3 is a front plan view of FIG. 1.
FIG. 4 is a back plan view of FIG. 1.
FIG. 5 is a right plan view of FIG. 1.
FIG. 6 is a left plan view of FIG. 1.
FIG. 7 is a top plan view of FIG. 1.
FIG. 8 is a bottom plan view of FIG. 1.
FIG. 9 is a front perspective view of a second embodiment of the firebox.
FIG. 10 is a back perspective view of FIG. 9.
FIG. 11 is a front plan view of FIG. 9.
FIG. 12 is a back plan view of FIG. 9.
FIG. 13 is a right plan view of FIG. 9.
FIG. 14 is a left plan view of FIG. 9.
FIG. 15 is a top plan view of FIG. 9.
FIG. 16 is a bottom plan view of FIG. 9.
FIG. 17 is a front perspective view of a third embodiment of the firebox.
FIG. 18 is a back perspective view of FIG. 17.
FIG. 19 is a front plan view of FIG. 17.
FIG. 20 is a back plan view of FIG. 17.
FIG. 21 is a right plan view of FIG. 17.
FIG. 22 is a left plan view of FIG. 17.
FIG. 23 is a top plan view of FIG. 17.
FIG. 24 is a bottom plan view of FIG. 17.
FIG. 25 is a front perspective view of a fourth embodiment of the firebox.
FIG. 26 is a back perspective view of FIG. 25.
FIG. 27 is a front plan view of FIG. 25.
FIG. 28 is a back plan view of FIG. 25.
FIG. 29 is a right plan view of FIG. 25.
FIG. 30 is a left plan view of FIG. 25.
FIG. 31 is a top plan view of FIG. 25; and,
FIG. 32 is a bottom plan view of FIG. 25.
The broken line showing is included for the purpose of illustrating portions of the article and forms no part of the claimed design.